John P. Carlin is an American attorney and former government official who served as the acting deputy attorney general in the United States Department of Justice from January to April of 2021. From April 2021 to September 2022, Carlin was principal associate deputy attorney general under Deputy Attorney General Lisa Monaco. He previously served as United States assistant attorney general for the National Security Division from April 2014 to October 15, 2016, and as chief of staff to Robert Mueller during his time as director of the Federal Bureau of Investigation.