Thomas Francis Brennan (October 10, 1853 – March 20, 1916) was an Irish-born prelate of the Catholic Church. He served as the first bishop of the Diocese of Dallas in Texas from 1891 to 1892 before serving as an auxiliary bishop of the Diocese of St. John's in the British Colony of Newfoundland from 1893 to 1905. Brennan's controversial actions and poor relations with clergy in both Dallas and St. John's led the Vatican to remove him from both posts and eventually place him in a monastery.