The March Constitution, Imposed March Constitution or Stadion Constitution (German: or ) was a "irrevocable" constitution of the Austrian Empire promulgated by Minister of the Interior Count Stadion between 4 March and 7 March 1849 until it was revoked by the New Year's Eve Patent () of Emperor Franz Joseph I on 31 December 1851. It had preempted the Kremsier Constitution of the Kremsier Parliament. This state of affairs would last until the October Diploma of 20 October 1860 and the later February Patent of 26 February 1861.