Plaintiff Diane Steck brought suit against Sakowitz, Inc. for tortious interference with the employment contract that Steck had with Oshman’s Sporting Goods, Inc. Steck sued because she was dismissed after the attorney for Sakowitz wrote Osh-man’s complaining that Oshman’s employment of Steck was a breach of Steck’s prior non-competition agreement with Sakowitz. The trial court granted Defendant Sakow-itz’s motion for summary judgment. The court of appeals reversed the judgment for Sakowitz and remanded the cause, holding that there were fact issues whether Sakow-itz acted in good faith in sending the letter to Oshman’s, whether Steck had signed the non-competition agreement and whether Sakowitz reasonably believed it had a legal interest to protect. 659 S.W.2d 91. At the trial court level, Steck also asserted a libel action against Sakowitz, but the court of appeals rejected that claim. Steck has abandoned that claim in this court and relies only on her claim that Sakowitz’s letter to Oshman’s was a tortious interference with her employment contract. We reverse the judgment of the court of appeals and affirm the judgment of the trial court that plaintiff Steck take nothing.
Sakowitz showed at the summary judgment hearing that Diane Steck went to work for Sakowitz in the fall of 1976 as a clerk. In February of 1977 Sakowitz selected her to participate in the company’s executive training program. The summary judgment proof, including Steck’s deposition, show that on February 23, 1978, at the beginning of Steck’s second year of training, Sakowitz distributed a non-competition agreement to the participants. Sa-kowitz explained to the executive trainees that, because it was making an investment in those participating, it did not want to train them for its competitors. Sakowitz required all of the trainees to sign the agreement and explained that those who did not sign it would be dropped from the program. Steck’s continued employment in her position as an assistant buyer was not, however, conditioned upon her participation in the training program.
Steck signed her name on the first page of the contract in the space provided for name identification. She did not sign the document on the signature line at the end of the four-page document. She returned the document without signing it at the end of the document because she didn’t think Sakowitz’s reasons for the contract were valid, and she hoped that her failure to sign “would slip by,” and “nobody would notice it.”
Steck continued in and completed the training program fifteen months later in May 1979. She continued her work with Sakowitz as an assistant buyer for gifts and stationery. Four months after completing the program, she left Sakowitz and began working for Oshman’s as a buyer of gifts and stationery, the skill for which Sakowitz had trained her.
Sakowitz’s attorney wrote two letters: one to Steck and another to Oshman’s. The letter to Steck informed Steck that her new employment with Oshman’s violated her non-competition agreement. Sakow-itz’s letter to Oshman’s advised that Sa-kowitz had a contract with Steck that prohibited her for one year from working for an entity engaged in the operation of a *107specialty or department store in Harris County. The letter asked that Oshman’s honor the terms of Sakowitz’s contract and advised that failure to do so would leave no alternative “but to consider legal action against your company.” Oshman’s terminated Steck’s employment after receipt of the letter. It is the letter to Oshman’s that is the basis of Steck’s claim that Sakowitz is liable for tortious interference with her employment contract with Oshman’s.
Sakowitz’s attorney, who prepared and sent the letter to Oshman’s, showed by affidavit at the summary judgment hearing that he sent the letter to protect the rights of his client only after careful study and with no ill will or malice but in the good faith belief that under the applicable law, Steck had agreed not to compete. In City of Houston v. Clear Creek Basin Authority, 589 S.W.2d 671 (Tex.1979), we held that pleadings do not constitute summary judgment proof. We also held that a non-movant, like Steck, must come forward by written motion and sworn proof to controvert the summary judgment proof. Plaintiff Steck’s response to the motion for summary judgment included no sworn statement that Sakowitz acted without legal justification or excuse. She attached an unsworn brief about the law from which we infer that she contended that Sakowitz asserted an unfounded claim.
To establish the necessary elements for her claim of tortious interference, Steck had to show (1) that the defendant maliciously interfered with the contractual relationship and (2), without legal justification or excuse. Terry v. Zachry, 272 S.W.2d 157, 159 (Tex.Civ.App.—San Antonio 1954, writ ref’d n.r.e.). In Morris v. Jordan Financial Corp., 564 S.W.2d 180,184 (Tex.Civ.App.—Tyler 1978, writ ref’d n.r.e.), malice was defined as an act without excuse or just cause. One is privileged to interfere with a contract of another if it is done in the bona fide exercise of his own rights or if he has an equal or superior right in the subject matter to that of the plaintiff. Black Lake Pipe Line Co. v. Union Construction Co., 538 S.W.2d 80, 91 (Tex.1976). This privilege extends to the actual assertion or threatened assertion of rights. Morris v. Jordan Financial Corp., 564 S.W.2d 180, 184 (Tex.Civ.App.— Tyler 1978, writ ref’d n.r.e.).
Many lawsuits and claims are asserted even though their validity is not absolute. The uncertainty of a dispute is often the reason that one resorts to the courthouse for a resolution. In analogous situations, the failure to prevail after the institution and prosecution of a suit is not regarded as malicious. Salado College v. Davis, 47 Tex. 131, 135-36 (1877); Butler v. Morgan, 590 S.W.2d 543, 545 (Tex.Civ.App.—Houston [1st Dist.] 1979, writ ref’d n.r.e.). The basis for the rule is that good faith litigants should be assured access to the judicial system. One may not recover in an action for malicious prosecution because the opposing party was mistaken about the strength of a claim. Smith v. Adams, 27 Tex. 28, 29-30 (1863); Martin v. Trevino, 578 S.W.2d 763, 768 (Tex.Civ.App. —Corpus Christi 1978, writ ref’d n.r.e.).
The similar rule applicable to suits for tortious interference with contracts as stated in Tidal Western Oil Corp. v. Shackelford, 297 S.W. 279 (Tex.Civ.App.—Fort Worth 1927, writ ref’d), is:
It would be a strange doctrine indeed to hold that a person having a well grounded and justifiable belief of a right in or to property may be held liable in damages because of an assertion of such a right.
Id. at 281.
Sakowitz was privileged to assert its claim to the noncompetition agreement, grounded upon estoppel theory or an oral contract, even though that claim may be doubtful, so long as it asserted a colorable legal right. Hardin v. Majors, 246 S.W. 100, 102 (Tex.Civ.App.—Amarillo 1923, no writ). See also Garza v. Mitchell, 607 S.W.2d 593, 600 Tex.Civ.App.—Tyler 1980, no writ); Terry v. Zachry, 272 S.W.2d 157, 159 (Tex.Civ.App.—San Antonio 1954, writ ref’d n.r.e.).
We hold that Sakowitz made a showing of its legal justification, but Steck produced *108no summary judgment evidence to raise a fact question regarding the lack of justification for Sakowitz’s letter to Oshman’s. Therefore, Steck failed to raise an issue about one of the two necessary elements to prevail on a tortious interference cause of action.
We reverse the judgment of the court of appeals and affirm the judgment of the trial court.
WALLACE, J., dissents with opinion in which CAMPBELL and RAY, JJ., join. KILGARLIN, J., not sitting.