| Cornelius Leary | |
| State: | Maryland |
| Term Start: | March 4, 1861 |
| Term End: | March 3, 1863 |
| Predecessor: | J. Morrison Harris |
| Successor: | Henry Winter Davis |
| Office2: | Member of the Maryland House of Delegates |
| Term Start2: | 1838 |
| Term End2: | 1839 |
| Birth Name: | Cornelius Lawrence Ludlow Leary |
| Birth Date: | 22 October 1813 |
| Birth Place: | Baltimore, Maryland, U.S. |
| Death Place: | Baltimore, Maryland, U.S. |
| Resting Place: | Lorraine Cemetery |
| Party: | Unionist |
| Otherparty: | Know Nothing Whig |
| Profession: | Politician, lawyer |
Cornelius Lawrence Ludlow Leary (October 22, 1813 – March 21, 1893) was an American politician from Maryland.
Leary was born in Baltimore, Maryland, and attended the public schools. He graduated from St. Mary's College of Baltimore in 1833, and afterwards moved to Louisville, Kentucky. He returned to Baltimore in 1837, and served as a Whig member of the Maryland House of Delegates in 1838 and 1839. He studied law, was admitted to the bar in 1840, and commenced practice in Baltimore. He was also a presidential elector on Maryland's victorious American Party ticket in 1856.
Leary was elected as a Unionist to the Thirty-seventh Congress, where he served from March 4, 1861, to March 3, 1863. After his term in Congress, he resumed the practice of law in Baltimore, where he died. He is interred in Lorraine Cemetery.