A Decree of Muharram or Firman of Muharram is any of a number of decrees or firmans issued by the Ottoman Empire in the Islamic month of Muharram. The most important of which, both issued by ‘Abdu’l-Hamid II during the decline of the Ottoman Empire, are:

• Firman issued in Muharram 1299 AH (December 1881 CE) which turned over a large proportion of the Ottoman Empire's revenue to the Public Debt Administration for the repayment of foreign creditors, practically bankrupting the Ottomans after the Russo-Turkish War, 1877-1878.
• Firman issued on 5 Muharram 1311 AH (18 July 1893 CE) which regarded the appointment of a Chief Rabbi of Jerusalem and the rights of the Jewish community in that province.^[1]

Additionally, Decree of Muharram may refer to the Islamic tradition that it is unlawful (haraam) to go to war in the month of Muharram.