Gagan Ajit Singh (born 9 December 1980) is an Indian former field hockey player who played as a forward.

Gagan Ajit Singh was born on 9 December 1980 in Firozpur, a city in the Indian State of Punjab.

Gagan Ajit was educated at the Union Academy Senior Secondary School and Jamia Millia Islamia in New Delhi.

In 1997, he was selected by New Delhi's Air India Hockey Academy to compete in the junior national tournament.

Singh played at the 2000 and the 2004 Summer Olympics, with India finishing in seventh place on both occasions.