| Type: | Bishop |
| Honorific-Prefix: | Most Reverend |
| Antonio Leoncillo | |
| Bishop of Termoli | |
| Church: | Catholic Church |
| Diocese: | Diocese of Termoli |
| Term: | 1651–1653 |
| Predecessor: | Cherubino Manzoni |
| Successor: | Carlo Mannello |
| Consecration: | 9 Jul 1651 |
| Consecrated By: | Marcantonio Franciotti |
| Birth Place: | Spoleto, Italy |
| Death Date: | 1653 |
Antonio Leoncillo or Antonio Leoncello or Antonio Leoncilli (died c. 1653) was a Roman Catholic prelate who served as Bishop of Termoli (1651–1653?).
Antonio Leoncillo was born in Spoleto, Italy.On 3 July 1651, he was appointed during the papacy of Pope Innocent X as Bishop of Termoli.
On 9 July 1651, he was consecrated bishop by Marcantonio Franciotti, Cardinal-Priest of Santa Maria della Pace.
He served as Bishop of Termoli until his death in 1653.