delivered the opinion of the Court.
In 1979, following a year of study and public comment, the Environmental Protection Agency (EPA) promulgated standards limiting the emission of sulfur dioxide by coal-burning powerplants. Both respondents in this case — the Environmental Defense Fund (EDF) and the Sierra Club— filed petitions for review of the agency’s action in the United States Court of Appeals for the District of Columbia Circuit. EDF argued that the standards promulgated by the EPA were tainted by the agency’s ex parte contacts with representatives of private industry, while the Sierra Club contended that EPA lacked authority under the Clean Air Act to issue the type of standards that it did. In a lengthy opinion, the Court of Appeals rejected all the claims of both EDF and the Sierra Club. Sierra Club v. Costle, 211 U. S. App. D. C. 336, 657 F. 2d 298 (1981).
Notwithstanding their lack of success on the merits, EDF and the Sierra Club filed a request for attorney’s fees incurred in the Sierra Club action. They relied on § 307(f) of the Clean Air Act, 91 Stat. 777, 42 U. S. C. § 7607(f) (1976 ed., Supp. V), which permits the award of attorney’s fees in certain proceedings “whenever [the court] determines that *682such award is appropriate.” Respondents argued that, despite their failure to obtain any of the relief they requested, it was “appropriate” for them to receive fees for their contributions to the goals of the Clean Air Act. The Court of Appeals agreed with respondents, ultimately awarding some $45,000 to the Sierra Club and some $46,000 to EDF. Sierra Club v. Gorsuch, 217 U. S. App. D. C. 180, 672 F. 2d 33 (1982); Sierra Club v. Gorsuch, 221 U. S. App. D. C. 450, 684 F. 2d 972 (1982). We granted certiorari, 459 U. S. 942 (1982), to consider the important question decided by the Court of Appeals.1
I
The question presented by this case is whether it is “appropriate,” within the meaning of § 307(f) of the Clean Air Act, to award attorney’s fees to a party that achieved no success on the merits of its claims. We conclude that the language of the section, read in the light of the historic principles of fee-shifting in this and other countries, requires the conclusion that some success on the merits be obtained before a party becomes eligible for a fee award under § 307(f).
A
Section 307(f) provides only that:
“In any judicial proceeding under this section, the court may award costs of litigation (including reasonable attor*683ney and expert witness fees) whenever it determines that such award is appropriate.” 91 Stat. 777, 42 U. S. C. §7607(f) (1976 ed., Supp. V) (emphasis added).
It is difficult to draw any meaningful guidance from § 307 (f )’s use of the word “appropriate,” which means only “specially suitable: fit, proper.” Webster’s Third New International Dictionary 106 (1976).2 Obviously, in order to decide when fees should be awarded under § 307(f), a court first must decide what the award should be “specially suitable,” “fit,” or “proper” for. Section 307(f) alone does not begin to answer this question, and application of the provision thus requires reference to other sources, including fee-shifting rules developed in different contexts. As demonstrated below, inquiry into these sources shows that requiring a defendant, completely successful on all issues, to pay the unsuccessful plaintiff’s legal fees would be a radical departure from longstanding fee-shifting principles adhered to in a wide range of contexts.
B
Our basic point of reference is the “American Rule,” see Alyeska Pipeline Co. v. Wilderness Society, 421 U. S. 240, *684247 (1975) (emphasis added), under which even “the prevailing litigant is ordinarily not entitled to collect a reasonable attorneys’ fee from the loser.” It is clear that generations of American judges, lawyers, and legislators, with this rule as the point of departure, would regard it as quite “inappropriate” to award the “loser” an attorney’s fee from the “prevailing litigant.” Similarly, when Congress has chosen to depart from the American Rule by statute, virtually every one of the more than 150 existing federal fee-shifting provisions predicates fee awards on some success by the claimant; while these statutes contain varying standards as to the precise degree of success necessary for an award of fees — such as whether the fee claimant was the “prevailing party,”3 the “substantially prevailing” party,4 or “successful”5 — the consistent rule is that complete failure will not justify shifting fees from the losing party to the winning party. Also instructive is Congress’ reaction to a draft of the Equal Access to Justice Act, which permitted shifting fees from losing parties to the Government, if “in the interest of justice,” S. 2354, 95th Cong., 2d Sess. (1978). This provision, criticized by the Justice Department as a “radical” departure from traditional principles, was rejected by Congress.6 Finally, English courts have awarded counsel fees to successful litigants for 750 years, see *685Alyeska, supra, at 247, n. 18, but they have never gone so far as to force a vindicated defendant to pay the plaintiff’s legal expenses.
While the foregoing treatments of fee-shifting differ in many respects, they reflect one consistent, established rule: a successful party need not pay its unsuccessful adversary’s fees. The uniform acceptance of this rule reflects, at least in part, intuitive notions of fairness to litigants. Put simply, ordinary conceptions of just returns reject the idea that a party who wrongly charges someone with violations of the law should be able to force that defendant to pay the costs of the wholly unsuccessful suit against it. Before we will conclude Congress abandoned this established principle that a successful party need not pay its unsuccessful adversary’s fees — rooted as it is in intuitive notions of fairness and widely manifested in numerous different contexts — a clear showing that this result was intended is required.7
Also relevant in deciding whether to accept the reading of “appropriate” urged by respondents is the fact that § 307(f) affects fee awards against the United States, as well as against private individuals. Except to the extent it has waived its immunity, the Government is immune from claims for attorney’s fees, Alyeska, supra, at 267-268, and n. 42. Waivers of immunity must be “construed strictly in favor of the sovereign,” McMahon v. United States, 342 U. S. 25, 27 (1951), and not “enlarge[d] . . . beyond what the language requires.” Eastern Transportation Co. v. United States, *686272 U. S. 675, 686 (1927). In determining what sorts of fee awards are “appropriate,” care must be taken not to “enlarge” §307(f)’s waiver of immunity beyond what a fair reading of the language of the section requires.
Given all the foregoing, we fail to find in § 307(f) the requisite indication that Congress meant to abandon historic fee-shifting principles and intuitive notions of fairness when it enacted the section. Instead, we believe that the term “appropriate” modifies but does not completely reject the traditional rule that a fee claimant must “prevail” before it may recover attorney’s fees. This result is the most reasonable interpretation of congressional intent.
M HH
Respondents make relatively little effort to dispute much of the foregoing, devoting their principal attention to the legislative history of § 307(f). Respondents’ arguments rest primarily on the following excerpt from the 1977 House Report on § 307(f):8
*687“The committee bill also contains express authority for the courts to award attorneys [sic] fees and expert witness fees in two situations. The judicial review proceedings under section 307 of the act when the court determines such award is appropriate [sic].
“In the case of the section 307 judicial review litigation, the purposes of the authority to award fees are not only to discourage frivolous litigation, but also to encourage litigation which will assure proper implementation and administration of the act or otherwise serve the public interest. The committee did not intend that the court’s discretion to award fees under this provision should be restricted to cases in which the party seeking fees was the ‘prevailing party.’ In fact, such an amendment was expressly rejected by the committee, largely on the grounds set forth in NRDC v. EPA, 484 F. 2d 1331, 1388 [sic] (1st Cir. 1973).” H. R. Rep. No. 95-294, p. 337 (1977) (emphasis added).
In determining the meaning of the Senate Report’s rejection of the “prevailing party” standard it first is necessary to ascertain what this standard was understood to mean. When § 307(f) was enacted, the “prevailing party” standard had been interpreted in a variety of rather narrow ways. See, e. g., Taylor v. Safeway Stores, Inc., 524 F. 2d 263, 273 (CA10 1975); Pearson v. Western Electric Co., 542 F. 2d 1150 (CA10 1976); Best Medium Publishing Co. v. National Insider, Inc., 385 F. 2d 384, 386 (CA7) (the “‘prevailing party’ *688is the one who prevails as to the substantial part of the litigation”), aff’g 259 F. Supp. 433 (ND Ill. 1967); Dobbins v. Local 212, Int’l Brotherhood of Electrical Workers, AFL-CIO, 292 F. Supp. 413, 450 (SD Ohio 1968); Goodall v. Mason, 419 F. Supp. 980 (ED Va. 1976); Clanton v. Allied Chemical Corp., 409 F. Supp. 282 (ED Va. 1976). Some courts — although, to be sure, a minority — denied fees to plaintiffs who lacked a formal court order granting relief, while others required showings not just of some success, but “substantial” success. Indeed, even today, courts require that, to be a “prevailing party,” one must succeed on the “central issue,” Coen v. Harrison County School Bd., 638 F. 2d 24, 26 (CA5 1981), or “essentially succee[d] in obtaining the relief he seeks in his claims on the merits,” Bagby v. Beal, 606 F. 2d 411, 415 (CA3 1979). See also Hensley v. Eckerhart, 461 U. S. 424, 433, n. 8 (1983).
These various interpretations of the “prevailing party” standard provide a ready, and quite sensible, explanation for the Senate Report’s discussion of § 307(f). Section 307(f) was meant to expand the class of parties eligible for fee awards from prevailing parties to partially prevailing parties— parties achieving some success, even if not major success.9 Put differently, by enacting § 307(f), Congress intended to eliminate both the restrictive readings of “prevailing party” adopted in some of the cases cited above and the necessity for case-by-case scrutiny by federal courts into whether plaintiffs prevailed “essentially” on “central issues.”
This view of the “when appropriate” standard is confirmed by the language of a forerunner of § 307, § 36 of S. 252, 95th Cong., 1st Sess. (1977):
*689“(d) In any judicial proceeding under this Act in which the United States ... is a party.. . any party other than the United States which prevails in such action shall recover from the United States the reasonable costs for such party’s participation in such proceeding, including reasonable attorney’s fees. ... In any case in which such party prevails in part, the court shall have discretion to award such reasonable costs.” (Emphasis added.)
This provision was described, in the legislative history, as follows:
“This section amends section 307 of existing law. In any suit in which the United States is a party, any prevailing party . . . shall recover all reasonable costs of its participation in such proceeding. Where such party prevails in part, the court may award reasonable costs.”10
It is clear from the distinction drawn in these two passages that — as the case law discussed above fairly indicated — Congress understood “prevailing party” and “partially prevailing party” as two quite different things, with the former encompassing only a limited category of parties that achieved success in their lawsuits. The “prevailing party” category was thought not to extend to parties who prevailed only in part.
Given this, the House Report’s statement that “the court’s discretion. .. should [not] be restricted to cases in which the party seeking fees was the ‘prevailing party,’” H. R. Rep. No. 95-294, p. 337 (1977) (emphasis added), provides little, if any, support for the theory that completely unsuccessful plaintiffs may receive fees. Rather, the sentence, fairly read, means only that fees may be awarded to all parties who prevail in part as w.ell as those who prevail in full: it rejects the restrictive notions of “prevailing party” adopted *690in Pearson, supra, and like cases, as well as difficult questions of what constitutes a “central” issue, or “essential” success. The Report, however, does not give any real support to the view that Congress meant to depart from the long-established rule that complete winners need not pay complete losers for suing them.11
This straightforward reading of the House Report finds support in Natural Resources Defense Council, Inc. v. EPA, 484 F. 2d 1331 (CA1 1973), cited in the Report. There, the court considered whether fees should be denied under § 304(d) “because some issues were decided adversely to petitioners.” Id., at 1338. This argument was rejected, primarily because “petitioners were successful in several major respects; they should not be penalized for having also advanced some points of lesser weight.” Ibid, (emphasis added). Needless to say, this holding does not mean that even if a party is unsuccessful in all respects, it still may *691recover fees from its opponent. Rather, the court’s decision provides precise support for the view, urged above, that adoption of the “when appropriate” standard was intended to permit awards of fees to all partially prevailing parties. After all, this was just what the facts were in NRDC v. EPA.
The foregoing reading of § 307(f) also finds support in other aspects of the legislative history. For example, § 307(f), as enacted, was regarded as narrower than the attorney’s fee provision in S. 252, which, as mentioned above, was a forerunner of § 307(f). A section-by-section analysis of S. 252 and § 307(f) stated that the “conference report [setting out the current ‘when appropriate’ standard] contained a narrower House provision” than S. 252. Section-by-Section Analysis, swpra n. 10, at 37. Yet, as the quotation, supra, at 689, shows, S. 252 permitted fee awards only to prevailing and partially prevailing parties, and not to completely losing parties. The statement that the current language of § 307(f) is “narrower” than S. 252 strongly suggests that losing parties were not intended to recover fee awards under the section. Moreover, the view that § 307(f) was “narrow” hardly comports with the somewhat radical departure from well-settled legal principles urged by respondents.
In addition, the relation between §§ 304(d) and 307(f) is instructive. Like § 307(f), § 304(d) provides that a court may award fees when “appropriate.” Importantly, however, suits may be brought under § 304 against private parties alleged to be in violation of the requirements of the Clean Air Act. It is clear, as explained below, that, whatever general standard may apply under § 307(f), a similar standard applies under § 304(d). In Northcross v. Memphis Bd. of Ed., 412 U. S. 427 (1973), we held that similar attorney’s fee provisions should be interpreted pari passu, and read the “prevailing party” standard in 20 U. S. C. § 1617 as identical to that in 42 U. S. C. §2000a-3(b). In Hensley, 461 U. S., at 433, n. 7, we held that “the standards set forth . . . are *692generally applicable to all cases in which Congress has authorized an award of fees to a ‘prevailing party.’” See also BankAmerica, Corp. v. United States, 462 U. S. 122, 129 (1983). Thus, it is clear, at least as a general principle, that awards of attorney’s fees under § 304(d) will be “appropriate” in circumstances similar to those that are “appropriate” under § 307(f).
Given the foregoing, respondents’ argument that fee awards are available even to unsuccessful plaintiffs encounters yet further difficulties. Section 304 suits may be brought against private businesses by any private citizen. Such suits frequently involve novel legal theories, theories that the EPA has rejected. After protracted litigation requiring payment of expensive legal fees and associated costs in both money and manpower, the private defendant may well succeed in refuting each charge against it — proving it was in complete compliance with every detail of the Clean Air Act. Yet, under respondents’ view of the Act, the defendant’s reward could be a second lawyer’s bill — this one payable to those who wrongly accused it of violating the law. We simply do not believe that Congress would have intended such a result without clearly saying so.12
Finally, as shown in the margin,13 the central purpose of § 304(d) was to check the “multiplicity of [potentially merit-*693less] suits,” that Congress feared would follow the authorization of suits under the Clean Air Act, which was seen as an “unprecedented” innovation. One might well imagine the surprise of the legislators who voted for this section as an instrument for deterring meritless suits upon learning that instead it could be employed to fund such suits.
I — I I — I I — Í
We conclude, therefore, that the language and legislative history of § 307(f) do not support respondents’ argument that the section was intended as a radical departure from established principles requiring that a fee claimant attain some success on the merits before it may receive an award of fees. Instead, we are persuaded that if Congress intended such a *694novel result — which would require federal courts to make sensitive, difficult, and ultimately highly subjective determinations — it would have said so in far plainer language than that employed here. Hence, we hold that, absent some degree of success on the merits by the claimant, it is not “appropriate” for a federal court to award attorney’s fees under § 307(f). Accordingly, the judgment of the Court of Appeals is
Reversed.
Sixteen federal statutes and § 304(d) of the Clean Air Act, 42 U. S. C. § 7604(d) (1976 ed., Supp. V), contain provisions for awards of attorney’s fees identical to § 307(f). See, e. g., Toxic Substances Control Act, 15 U. S. C. § 2618(d); Endangered Species Act, 16 U. S. C. § 1540(g)(4); Surface Mining Control and Reclamation Act, 30 U. S. C. § 1270(d) (1976 ed., Supp. V); Deep Seabed Hard Mineral Resources Act, 30 U. S. C. § 1427(c) (1976 ed., Supp. V); Clean Water Act, 33 U. S. C. § 1365(d); Marine Protection, Research and Sanctuaries Act, 33 U. S. C. § 1415(g)(4); Deep-water Port Act, 33 U. S. C. § 1515(d); Safe Drinking Water Act, 42 U. S. C. § 300j — 8(d); Noise Control Act, 42 U. S. C. § 4911(d); Energy Policy and Conservation Act, 42 U. S. C. § 6305(d); Powerplant and Industrial Fuel Use Act, 42 U. S. C. § 8435(d) (1976 ed., Supp. V); Ocean Thermal *683Energy Conversion Act, 42 U. S. C. § 9124(d) (1976 ed., Supp. V); and Outer Continental Shelf Lands Act, 43 U. S. C. § 1349(a)(6) (1976 ed., Supp. V). As explained below, the interpretation of “appropriate” in § 307(f) controls construction of the term in these statutes.
Dissenting from an award of fees under § 307(f) by the Court of Appeals for the District of Columbia Circuit, Judge Wilkey noted “the absence of any clue as to the meaning of ‘appropriate,’ ” and wrote that “there is no comprehensible or principled meaningfor ‘appropriate.’ ” Alabama Power Co. v. Gorsuch, 217 U. S. App. D. C. 148, 171, 179, 672 F. 2d 1, 24, 32 (1982). The Senate Report to § 307 also illustrates the lack of guidance provided by the plain language of the section. The Report observed that “[t]he purpose of the amendment to section 307 is to carry out the intent of the committee in 1970 that a court may, in its discretion, award costs of litigation to a party bringing a suit under section 307 of the Clean Air Act.” S. Rep. No. 95-127, p. 99 (1977) (emphasis added). See also H. R. Rep. No. 95-294, p. 28 (1977).
See, e. g., 5 U. S. C. § 504(a)(1) (1982 ed.); Commodity Exchange Act, 7 U. S. C. § 18(f); Voting Rights Act of 1965, 42 U. S. C. § 1973Z(e); Civil Rights Attorney’s Fees Awards Act of 1976, 42 U. S. C. § 1988 (1976 ed., Supp. V).
See, e. g., Freedom of Information Act, 5 U. S. C. § 552(a)(4)(E); Privacy Act, 5 U. S. C. §§ 552a(g)(2)(B), 552a(g)(3)(B); Government in the Sunshine Act, 5 U. S. C. § 552b(i).
See, e. g., Real Estate Settlement Procedures Act, 12 U. S. C. § 2607(d)(2); Right to Financial Privacy Act, 12 U. S. C. § 3417(a)(4) (1982 ed.); Jewelers’ Liability Act, 15 U. S. C. § 298(c).
Equal Access to Courts: Hearing on S. 2354 before the Senate Subcommittee on Improvements in Judicial Machinery of the Committee on the Judiciary, 95th Cong., 2d Sess., 31, 50 (1978).
Indeed, when Congress has desired such a change it has said so expressly, as in 15 U. S. C. § 2605(c)(4)(A), permitting fee awards if a party “represents an interest which would substantially contribute to a fair determination of the issues,” even if the participant’s viéws are rejected. If Congress intended the truly radical departure from American and English common law and countless federal fee-shifting statutes that the Court of Appeals attributes to it, it no doubt would have used explicit language to this effect — as it did in 15 U. S. C. §2605.
Respondents also rely on a single sentence from the 1970 Senate Report:
“The Courts should recognize that in bringing legitimate actions under this section citizens would be performing a public service and in such instances the courts should award costs of litigation to such party. This should extend to plaintiffs in actions which result in successful abatement but do not reach a verdict. For instance, if as a result of a citizen proceeding and before a verdict is issued, a defendant abated a violation, the court may award litigation expenses borne by the plaintiffs in prosecuting such actions.” S. Rep. No. 91-1196, p. 38 (emphasis added).
The approval of fee awards in “legitimate” actions offers respondents little comfort: “legitimate” means “being exactly as proposed: neither spurious nor false,” which does not describe respondents’ claims in this case. Respondents contend, however, that Congress intended the term “appropriate” to encompass situations beyond those mentioned in the legislative history, and, therefore, that the term reaches even totally unsuccessful actions. This is, of course, possible, but not likely. Congress found it necessary to explicitly state that the term appropriate “extended” to suits that forced defendants to abandon illegal conduct, although without a formal *687court order; this was no doubt viewed as a somewhat expansive innovation, since, under then-controlling law, see infra, some courts awarded fees only to parties formally prevailing in court. We are unpersuaded by the argument that this same Congress was so sure that “appropriate” also would extend to the far more novel, costly, and intuitively unsatisfying result of awarding fees to unsuccessful parties that it did not bother to mention the fact. If Congress had intended the far-reaching result urged by respondents, it plainly would have said so, as is demonstrated by Congress’ careful statement that a less sweeping innovation was adopted.
Of course, we do not mean to suggest that trivial success on the merits, or purely procedural victories, would justify an award of fees under statutes setting out the “when appropriate” standard. Rather, Congress meant merely to avoid the necessity for lengthy inquiries into the question whether a particular party’s success was “substantial” or occurred on a “central issue.”
Section-by-Section Analysis of S. 252 and S. 253, Prepared by the Staff of the Subcommittee on Environmental Pollution of the Senate Committee on Environment and Public Works, Serial No. 95-2, p. 36 (Comm. Print 1977) (emphasis added).
Respondents observe that Congress failed to adopt the attorney’s fee provision contained in S. 252, discussed above, requiring fee awards to “prevailing parties,” and permitting awards to “partially prevailing parties.” They argue that Congress’ failure to adopt this rule indicates a desire to expand the availability of fee awards to parties not prevailing in any degree. The argument is unpersuasive. Congress almost certainly rejected the provision because it required fee awards to “prevailing parties.” This rule was specifically criticized by several groups commenting on the proposed legislation. One group wrote: “[W]e strongly oppose Section 36 of S. 252. We see no basis for automatically providing court costs and attorney’s fees for parties prevailing in litigation pursuant to the Act. If such parties represent a widespread public interest, they should be able to finance themselves.” See 5 Legislative History of the Clean Air Act Amendments of 1977 (Committee Print compiled for the Senate Committee on Environment and Public Works by the Library of Congress), Ser. No. 95-16, pp. 4241, 4255 (1978) (Chamber of Commerce). Indeed, the Natural Resources Defense Council told Congress that the provision requiring fee awards to “prevailing parties was “fundamentally unwise” and “wholly unprecedented in American law”: it urged that the provision be rejected. Id., at 4092. It is obvious, therefore, that S. 252 was rejected not because it was too restrictive in its awarding of fees, but because it required, rather than permitted awards of attorney’s fees.
We do not mean to suggest that private parties should be treated in exactly the same manner as governmental entities. Differing abilities to bear the cost of legal fees and differing notions of responsibility for fulfilling the goals of the Clean Air Act likely would justify exercising special care regarding the award of fees against private parties.
Because, as just shown, §§ 304(d) and 307(f) have similar meanings, the history of §304 is relevant to a construction of § 307(f). The 1970 Clean Air Amendments contained a new concept — the statutory authorization of “citizens suits,” allowing private citizens to sue any person violating the Clean Air Act. This provision attracted vehement opposition in Congress.- Senator Hruska, for example, read a memorandum observing that the section “is unprecedented in American history.’’ 1 Legislative History of the Clean Air Amendments of 1970 (Committee Print compiled for the Senate Committee on Public Works by the Library of Congress) Ser. *693No. 93-18, p. 277 (1974) (Senate debate on S. 4358, Sept. 21, 1970). The memorandum predicted that § 304 “will result in a multiplicity of suits which will interfere with the Executive’s capability of carrying out its duties” and warned that § 304’s “open invitation to the institution of Citizens Suits” would “impose an impossible burden on the already burdened judicial system.” Id., at 278.
The principal response to these concerns was as follows:
“The Senator from Nebraska raised the question of possible harassing suits by citizens. This the committee attempted to discourage by providing that the costs of litigation — including counsel fees — may be awarded by the courts to the defendants in such cases, so that the citizen who brings a harassing suit is subject not only to the loss of his own costs of litigation, but to the burden of bearing the costs of the parties against whom he has brought the suit in the first instance. I doubt very much that individual citizens would lightly engage this possibility.” Id., at 280.
This point was repeated in the Senate Report:
“Concern was expressed that some lawyers would use section 304 to bring frivolous and harassing actions. The Committee has added a key element in providing that the courts may award costs of litigation, including reasonable attorney and expert witness fees, whenever the court determines that such action is in the public interest. The court could thus award costs of litigation to defendants where the litigation was obviously frivolous or harassing. This should have the effect of discouraging abuse of this provision, while at the same time encouraging the quality of the actions that will be brought.” S. Rep. No. 91-1196, p. 38 (1970).