Carol Duhurst Leonnig is an American investigative journalist. She was a staff writer at The Washington Post from 2000 to 2025 and was part of a team that won the 2014 Pulitzer Prize for Public Service for reporting on the NSA's expanded spying on Americans. Leonnig also received Pulitzer Prizes for National Reporting in 2015 and 2018. In August 2025, she became a senior investigative correspondent for MSNBC.

Leonnig began her reporting career in 1989 at The Philadelphia Inquirer.