Section 39, Article III, Texas Constitution, provides that “No law passed by the Legislature, except the general appropriation act, shall take effect or go into force until ninety days after the adjournment of the session at which it was enacted, unless the Legislature shall, by a vote of two-thirds of all the members elected to each House, otherwise direct.” If an act does not specify an effective date, the act becomes effective on the 91st day after the date of final adjournment.

If the act specifies an effective date earlier than the 91st day after adjournment, and the effective date rule is suspended, the act becomes effective on the specified date. If the act specifies that it has immediate effect, and the effective date rule is suspended, the act becomes effective on the date of the last action necessary for it to become law, which is: (1) the date the governor approves the act; (2) the date the governor files the act with the secretary of state (having neither approved nor vetoed it); (3) the date the appropriate period for gubernatorial action expires, if the governor fails to act within that period (Section 14, Article IV, Texas Constitution); or (4) in the event of a veto, the date the veto is overridden.

The act can specify an effective date after the 91st day after adjournment without suspending the effective date rule, make the effective date contingent on an event or the expiration of a specified period after that event takes place, or make it contingent on the adoption of a proposed constitutional amendment. Parts of a bill can take effect on different dates, or particular sections or applications of an act may be delayed or accelerated.