Texas Penal Code - PENAL § 9.61. Parent-Child

(a) The use of force, but not deadly force, against a child younger than 18 years is justified:

(b) For purposes of this section, “in loco parentis” includes grandparent and guardian, any person acting by, through, or under the direction of a court with jurisdiction over the child, and anyone who has express or implied consent of the parent or parents.