Gary Leonard Ackerman (born November 19, 1942) is a New York politician, currently the representative for the state's 5th Congressional district (map) in the U.S. House.

Ackerman was born in Brooklyn, New York. He attended St. John's University for a short time. Ackerman worked as a teacher in the 1960s. After the birth of his daughter, he petitioned for an unpaid leave of absence to spend time with his newborn daughter but the New York school district rejected his request since their policy only allowed female employees to take unpaid leave. Ackerman then successfully sued the district and established that parents of either gender could go on unpaid maternity leave.

He was elected to the state senate as a Democrat in 1978. He served as a state senator until 1983. He was elected to the House of Representatives in a special election in 1983.

As a Congressman, Ackerman has served in the House International Relations Committee. He made history as the first American since the Korean War to cross the DMZ