The Ottoman Armenian population mostly belonged to either the Armenian Apostolic Church or the Armenian Catholic Church. They were part of the Armenian millet until the Tanzimat reforms in the nineteenth century equalized all Ottoman citizens before the law. Armenians were a minority in the Empire. They played what would later be seen as a crucial role in Ottoman industry and commerce, and Armenian communities existed in almost every major city of the empire. Despite this, Armenians were heavily persecuted by the Ottoman authorities especially from the latter half of the 19th century, culminating in the Armenian Genocide.

The Ottoman Armenian population varied throughout history. The number of Armenians within the empire between 1914 and 1915 is a controversial topic. Most estimates by Western scholars range from 1.5 to 2.4 million. According to Britannica prior to 1915 and Samuel Cox, American Embassy in Istanbul from 1880-1886, it was 1.75 million and 2.4 million, respectively.