Tex. Education Code § 22.0511

(a) A professional employee of a school district is not personally liable for any act that is incident to or within the scope of the duties of the employee's position of employment and that involves the exercise of judgment or discretion on the part of the employee, except in circumstances in which a professional employee uses excessive force in the discipline of students or negligence resulting in bodily injury to students.

(b) This section does not apply to the operation, use, or maintenance of any motor vehicle.

(c) In addition to the immunity provided under this section and under other provisions of state law, an individual is entitled to any immunity and any other protections afforded under the Paul D. Coverdell Teacher Protection Act of 2001 (20 U.S.C. Section 6731 et seq.), as amended. Nothing in this subsection shall be construed to limit or abridge any immunity or protection afforded an individual under state law. For purposes of this subsection, "individual" includes a person who provides services to private schools, to the extent provided by federal law.

(d) A school district may not by policy, contract, or administrative directive:

(1) require a district employee to waive immunity from liability for an act for which the employee is immune from liability under this section; or

(2) require a district employee who acts in good faith to pay for or replace property belonging to a student or other person that is or was in the possession of the employee because of an act that is incident to or within the scope of the duties of the employee's position of employment.