The Succession to the Crown Act 2015 is the name of an act of the Commonwealth Parliament of Australia, enacted at the request of all six Australian states under section 51(xxxviii) of the Australian Constitution. The Australian acts were the final part of the Perth Agreement's legislative program agreed by the prime ministers of the Commonwealth realms to modernise the succession to the crowns of the sixteen Commonwealth realms, while continuing to have in common the same monarch and royal line of succession. as was the case at the time of the Statute of Westminster 1931.