Michael Joseph O'Farrell (December 2, 1832 – April 2, 1894) was an Irish-born prelate of the Roman Catholic Church who served as the first bishop of the Diocese of Trenton in New Jersey from 1881 until his death in 1894.

O'Farrell was ordained into the priesthood by Bishop John Ryan in Ireland on August 18, 1855.

[1] On August 11, 1881, O'Farrell was appointed the first bishop of the newly erected Diocese of Trenton by Pope Leo XIII.

According to historian John Gilmary Shea, O'Farrell's efforts to establish institutions to develop religion in the southern part of New Jersey "...did not fail to excite hostility".

During his tenure, O'Farrell erected several new parishes and missions, and established an orphanage in New Brunswick, New Jersey.