John Eric Ensign (born March 25, 1958) is the junior United States senator from Nevada. He is a member of the Republican Party. He was born in Roseville, California, but he and his family moved to Nevada when he was a child. He went to universities in Nevada, Oregon and Colarado and then became a successful businessman, particularly notable as a hotel and casino manager.

He quickly became successful at politics, being elected to the United States House of Representatives in 1994. He was reelected in 1996 but declined to run again in 1998. Instead he ran for the Senate but was defeated by the Democratic incumbent, Harry Reid. He gained a Senate seat after his second try in 2000, however, defeating his Democratic opponent to succeed the retiring Democratic incumbent, Richard Bryan.