Antonio Marenzi (22 September 1596 – 22 October 1662) was a Roman Catholic prelate who served as Bishop of Trieste (1646–1662) and Bishop of Pedena (1637–1646).

[2] On 30 January 1635, he was selected as Bishop of Pedena and confirmed by Pope Urban VIII on 17 August 1637.

[1][2] On 17 October 1638, he was consecrated bishop by Alessandro Cesarini (iuniore), Cardinal-Deacon of Sant'Eustachio, with Alfonso Gonzaga, Titular Archbishop of Rhodus, and Giovanni Battista Altieri, Bishop Emeritus of Camerino, serving as co-consecrators.

[2] On 26 April 1646, he was selected as Bishop of Trieste and confirmed by Pope Innocent X on 10 September 1646.

[1][2] He served as Bishop of Trieste until his death on 22 October 1662.