delivered the opinion of the Court,
in which Justice HECHT, Justice ENOCH, Justice OWEN and Justice O’NEILL joined.We must decide whether the court of appeals erred in dismissing as moot an appeal from a temporary injunction. The trial court granted Joel Casey Jones, then an offensive guard on the Texas Tech University Red Raiders’ football team, a temporary injunction enjoining the National Collegiate Athletic Association (“NCAA”) and Texas Tech University (“Texas Tech”) from enforcing NCAA rules that would have cost him his eligibility for the 1996 football season. Jones also sought and obtained an injunction prohibiting the NCAA from enforcing NCAA Operating Bylaw 19.8 (the “Restitution Rule”) against either Texas Tech or Jones. The Restitution Rule authorizes the NCAA to impose retroactive sanctions if an ineligible student-athlete competes under an injunction that is later voluntarily vacated, stayed or reversed, or found by the courts to have been improperly granted. The NCAA appealed, but the court of appeals declined the NCAA’s request to expedite the appeal. As a result, Jones played out the season and completed his eligibility before the appeal was resolved. Finding no justi-ciable controversy, the court of appeals dismissed the appeal as moot and vacated the injunction. 982 S.W.2d 450. Because we conclude that the appeal as a whole is not moot, we reverse the judgment of the court of appeals and remand to that court for consideration of the merits.
*85The NCAA is a voluntary, unincorporated association of colleges and universities created for the stated purpose of preserving the proper balance between athletics and scholarship in intercollegiate sports. Among other things, the NCAA promulgates rules and regulations to prevent any member institution from gaining an unfair competitive advantage in an athletic program. This case arose when Texas Tech, a member institution of the NCAA, declared Jones ineligible for the 1996 football season, Jones’s final year of eligibility.
Pursuant to NCAA rules, Texas Tech reported its action to the NCAA. However, the school also made repeated appeals for a waiver of the eligibility requirements, each of which the NCAA denied. Jones then filed a declaratory action against the NCAA and Texas Tech, seeking injunctive relief, damages, and attorney’s fees. Jones did not claim that he was eligible to play under NCAA rules. Instead, he contended that he relied on representations made to him by Texas Tech officials about the appropriate courses in which to enroll to retain his eligibility. According to Jones, Texas Tech was an agent of the NCAA when it made these statements, so that the NCAA became bound by the representations and was required to grant the waiver. The NCAA filed no claims for restitution against either Texas Tech or Jones, and Texas Tech made no claims against the NCAA.
The trial court first issued a temporary restraining order and then a temporary injunction that: (1) enjoined the NCAA and Texas Tech from taking any action to prevent Jones from participating as a member of Texas Tech’s football team, and (2) enjoined the NCAA from imposing any penalty on Jones or Texas Tech for complying with the court’s order and specifically enjoined the NCAA from enforcing the Restitution Rule, which would permit the NCAA to impose penalties such as forfeiture of individual records, performances and awards, forfeiture of team victories, records, performances and awards, and forfeiture of receipts from any competition in which the ineligible athlete participated.1 Although Texas Tech had not *86sought an injunction against the NCAA, the trial court presumably enjoined the NCAA from enforcing the Restitution Rule against the school based on Jones’s claim that he would be adversely affected if the NCAA were free to sanction Texas Tech.
The NCAA filed an interlocutory appeal pursuant to section 51.014(4) of the Texas Civil Practice and Remedies Code, arguing that the trial court abused its discretion in issuing the temporary injunction. Texas Tech was not a party to the appeal. The court of appeals dismissed the appeal as moot and vacated the injunction, holding that both portions of the injunction became inoperative when Texas Tech’s 1996 football season ended. 982 S.W.2d at 452. With regard to the portion of the injunction prohibiting the NCAA from imposing retroactive sanctions, the court of appeals further added that the injunction became inoperative at that time “because there was no justiciable controversy or pending action between Jones and the NCAA or the NCAA and Tech concerning the validity or enforcement of the restitution rule.” 982 S.W.2d at 452. In so holding, the court of appeals rejected the NCAA’s claim that its contractual right to impose retroactive sanctions under the Restitution Rule prevents the appeal of the temporary injunction from being moot. 982 S.W.2d at 451. We granted the NCAA’s petition for review.
Appellate courts are prohibited from deciding moot controversies. See Camarena v. Texas Employment Comm’n, 754 S.W.2d 149, 151 (Tex.1988). • This prohibition is rooted in the separation of powers doctrine in the Texas and United States Constitutions that prohibits courts from rendering advisory opinions. See Tex. Const, art. II, § 1; see also Texas Ass’n of Bus. v. Air Control Bd., 852 S.W.2d 440, 444 (Tex.1993); Firemen’s Ins. Co. v. Burch, 442 S.W.2d 331, 333 (Tex.1968). A case becomes moot if at any stage there ceases to be an actual controversy between the parties. See Camarena, 754 S.W.2d at 151. When a temporary injunction becomes inoperative due to a change in status of the parties or the passage of time, the issue of its validity is also moot. See Parr v. Stockwell, 159 Tex. 440, 322 S.W.2d 615, 616 (1959); Texas Educ. Agency v. Dallas Indep. Sch. Dist., 797 S.W.2d 367, 369 (Tex.App.—Austin 1990, no writ). An appellate court decision about a temporary injunction’s validity under such circumstances would constitute an impermissible advisory opinion. See generally Burch, 442 S.W.2d at 333; Texas Educ. Agency, 797 S.W.2d at 369.
Applying these well-established principles, the court of appeals concluded that the appeal from the temporary injunction order was moot as to both the portion of the injunction enjoining enforcement of the eligibility rules and the portion enjoining the enforcement of the Restitution Rule. 982 S.W.2d at 452. The NCAA argues, however, that a judicial determination about the validity of the temporary injunction remains important to resolve whether the NCAA may, contrary to the injunction’s dictate, take remedial action against Jones and Texas Tech under the Restitution Rule. Relying on several cases from other jurisdictions, the NCAA contends that there is still a live controversy between the parties because it could impose retroactive sanctions against Jones and Texas Tech if the court of appeals concludes that the trial court abused its discretion in prematurely granting Jones relief. See McPherson v. Michigan High Sch. Athletic Ass’n, 119 F.3d 453, 458-59 (6th Cir.1997); Pottgen v. Missouri State High Sch. Activities Ass’n, 40 F.3d 926, 928 (8th Cir.1994); Crane v. Indiana High Sch. Athletic Ass’n, 975 F.2d 1315, 1318-19 (7th Cir.1992); Wiley v. National Collegiate Athletic Ass’n, 612 F.2d 473, 475-76 *87(10th Cir.1979), cert. denied, 446 U.S. 943, 100 S.Ct. 2168, 64 L.Ed.2d 798 (1980); Cardinal Mooney High Sch. v. Michigan High Sch. Athletic Ass’n, 437 Mich. 75, 467 N.W.2d 21, 24 n. 4 (1991). According to the NCAA, dismissal of the case as moot would leave the rights of the parties undecided.
Jones counters that the NCAA’s restitution rights are moot because Bylaw 19.8 authorizes the NCAA to impose sanctions only if “[the] injunction ... is subsequently voluntarily vacated, stayed or reversed, or it is finally determined by the courts that injunctive relief is not or was not justified....” According to Jones, the rule does not authorize the NCAA to impose sanctions when an ineligible student-athlete competes under an injunction that becomes moot before further judicial action is taken. In short, Jones contends that the NCAA cannot rely on its restitution rights to avoid a finding of mootness because the NCAA has no restitution rights when the issue of the injunction’s validity becomes moot before being resolved by the courts.
The court of appeals erred in concluding that the second part of the temporary injunction — the portion restraining the NCAA from penalizing Texas Tech or Jones — became inoperative merely because the NCAA had no pending action against either Texas Tech or Jones to enforce its restitution rights or to establish the validity of the Restitution Rule. The NCAA could not have instituted such an action because it was enjoined from doing so and, until a higher court determined otherwise, was bound to follow the trial court’s order.2 See Tex.R. Civ. P. 692 (disobedience of an injunction is punishable as contempt of court). This portion of the injunction remained in effect after the 1996 football season ended, barring the NCAA from taking any action against Jones or Texas Tech under Rule 19.8 until the injunction was vacated by the court of appeals. This portion of the injunction would be moot, however, if either Jones or the NCAA, the only parties before the court of appeals, ceased to have a legally cognizable interest in the outcome of the appeal. See, e.g., Camarena, 754 S.W.2d at 151; see also Jordan v. Indiana High Sch. Athletic Ass’n, Inc., 16 F.3d 785, 788-89 (7th Cir.1994) (appeal moot because plaintiff had no interest that could be adversely affected by the outcome of the appeal). But if dismissal would leave the rights of the parties undecided, the issues involved are not moot and the appeal should have been decided on the merits.
The NCAA clearly has an interest in having the injunction invalidated and set aside; otherwise, it can never impose any penalties under the Restitution Rule. Whether Jones has a tangible interest in the continued validity of the injunction, however, is a closer issue. If dismissal of the appeal as moot and lifting of the injunction would affect Jones’s interest in the fruits of his intercollegiate participation during the 1996 football season, the appeal from the temporary injunction is not moot. See McPherson, 119 F.3d at 458-59; Sandison v. Michigan High Sch. Athletic Ass’n, 64 F.3d 1026, 1030 (6th Cir.1995); Pottgen, 40 F.3d at 928 (8th Cir.1994); Crane, 975 F.2d at 1318; Wiley, 612 F.2d 473 (10th Cir.1979); Manuel v. Oklahoma City Univ., 833 P.2d 288, 290 (Okla.App.1992). Thus, the issue is whether the NCAA could now take any action that would have an adverse effect of substantial significance to Jones if the court of appeals were to address the merits of the temporary injunction.
There is no indication in the record or the parties’ briefs as to whether Jones set any records or won any awards while participating under the injunction that could *88be stricken under the Restitution Rule. Likewise, the record does not reveal whether there are any team awards that could be stricken. The only remaining penalties that Jones could conceivably have an interest in avoiding are erasure of his individual performances, however that may be recorded for an offensive guard, and forfeiture of team victories.
There is some authority that the possibility of retroactive penalties does not prevent an appeal from being moot if the only possible penalty is forfeiture of team victories and the school, like Texas Tech in this case, is not a party to the appeal. See Johnson v. Florida High Sch. Activities Ass’n, Inc., 102 F.3d 1172, 1178 (11th Cir.1997); Jordan, 16 F.3d at 788-89. However, when a student-athlete represents to the trial court that he or she would personally be adversely affected if the school were penalized, courts have held that an appeal is not moot despite the absence of the school as a party on appeal. See McPherson, 119 F.3d at 458-59; Sandison, 64 F.3d at 1029-30. In seeking to prevent the NCAA from enforcing the Restitution Rule against Texas Tech, Jones specifically represented to the trial court that he would be adversely affected if the NCAA were not restrained from penalizing Tech. In addition to striking team victories, for example, the NCAA could also erase the records of Jones’s individual performance in each game played in under the injunction. See McPherson, 119 F.3d at 458-59 (despite having graduated from high school, student-athlete continued to have an interest in preventing forfeiture of his team’s victories and his own performances); Sandison, 64 F.3d at 1029-30 (same). Thus, we conclude that there is still a tangible and substantial controversy between the parties with respect to the portion of the injunction enjoining the NCAA from enforcing its restitution rights under Rule 19.8 against Jones and Tech. See McPherson, 119 F.3d at 458-59; Sandison, 64 F.3d at 1029-30. The court of appeals thus erred in holding that the appeal as a whole is moot.
Accordingly, we reverse the judgment of the court of appeals and remand the cause to that court for consideration of the merits of the appeal.
Justice ABBOTT filed a dissenting opinion, in which Justice BAKER, Justice HANKINSON and Justice GONZALES joined.. NCAA Operating Bylaw 19.8 provides:
If a student-athlete who is ineligible under the terms of the constitution, bylaws or other legislation of the Association is permitted to participate in intercollegiate competition contrary to such NCAA legislation but in accordance with the terms of a court restraining order or injunction operative against the institution attended by such student-athlete or against the Association, or both, and said injunction is subsequently voluntarily vacated, stayed or reversed or it is finally determined by the courts that injunctive relief is not or was not justified, the Council may take any one or more of the following actions against such institution in the interest of restitution and fairness to competing institutions:
(a) Require that individual records and performances achieved during participation by such ineligible student-athlete shall be vacated or stricken;
(b) Require that team records and performances achieved during participation by such ineligible student-athlete shall be vacated or stricken;
(c) Require that team victories achieved during participation by such ineligible student-athlete shall be abrogated and the games or events forfeited to the opposing institutions;
(d)Require that individual awards earned during participation by such ineligible student-athlete shall be returned to the Association, the sponsor or the competing institution supplying same;
(f) Determine that the institution is ineligible for one or more NCAA championships in the sports and in the seasons in which such ineligible student-athlete participated;
(g) Determine that the institution is ineligible for invitational and post-season meets and tournaments in the sports and in the seasons in which such ineligible student-athlete participated;
(h) Require that the institution shall remit to the NCAA the institution’s share of television receipts (other than the portion thereof shared with other conference members) for appearing on any live television series or program if such ineligible student-athlete participates in the contest(s) selected for such telecast, or if the Council concludes that the institution would not have been selected for such telecast but for the participation of such ineligible student-athlete during the season of the telecast; any such funds thus remitted shall be devoted to the NCAA postgraduate scholarship program; and
*86(i) Require that the institution that has been represented in an NCAA championship by such student-athlete shall return 90 percent of its share of the net receipts from such competition in excess of the regular expense reimbursement, or if said funds have not been distributed, require that they be withheld by the executive director.
. Nothing in the record indicates that the NCAA sought to stay the injunction. Although the NCAA filed an expedited interlocutory appeal challenging the propriety of in-junctive relief, the court of appeals overruled the NCAA’s "motion for priority appeal” and did not issue a ruling until after the 1996 football season ended.