Tex. Civ. Prac. & Rem. Code § 11.054
A court may find a plaintiff a vexatious litigant if the defendant shows that there is not a reasonable probability that the plaintiff will prevail in the litigation against the defendant and that:
(1) the plaintiff, in the seven-year period immediately preceding the date the defendant makes the motion under Section 11.051, has commenced, prosecuted, or maintained at least five litigations as a pro se litigant other than in a small claims court that have been:
(2) after a litigation has been finally determined against the plaintiff, the plaintiff repeatedly relitigates or attempts to relitigate, pro se, either:
Added by Acts 1997, 75th Leg., ch. 806, Sec. 1, eff. Sept. 1, 1997.
Acts 2013, 83rd Leg., R.S., Ch. 1224 (S.B. 1630), Sec. 3, eff. September 1, 2013.