János Simor (23 August 1813 – 23 January 1891) was a Hungarian prelate of the Catholic Church who was Archbishop of Esztergom from 1867 until his death in 1891.

He was ordained a priest on 28 October 1836 and for twenty years combined pastoral work with teaching and academic administration.

In 1854 Cardinal János Scitovszky dispatched him to Rome to make the case against expanding the planned Austrian concordat to include Hungary.

[3] At the First Vatican Council (1869-1870) he aligned himself with the minority who opposed the dogma of papal infallibility, though he later wrote in its defence.

[4] Pope Pius IX made him a cardinal priest on 22 December 1873[1] and he received the title of San Bartolomeo all'Isola on 15 June 1874.