Gaylord Anton Nelson (June 4, 1916 – July 3, 2005) was an American politician from Wisconsin who served as a United States senator and governor.

He practiced as a lawyer before serving in the United States Army, during which time he saw action in the Okinawa campaign during World War II.

In 1963 he convinced President John F. Kennedy to take a national speaking tour to discuss conservation issues.

Senator Nelson founded Earth Day, which began as a teach-in about environmental issues on April 22, 1970.

[6] During his 1968 re-election campaign, Nelson was praised by Vince Lombardi, the General Manager and former coach of the Green Bay Packers, as the "nation's #1 conservationist" at a banquet in Oshkosh.

[11] His office received a memorandum in 1975 stating that both Sominex and its competitor Compoz had been shown ineffective when compared to placebos, in spite of the US$34 million spent on sleeping aids in 1974.

The United Nations, with the U.S. supporting it, took the position in Cairo in 1994 that every country was responsible for stabilizing its own population.

"[15]He also rejected the suggestion that economic development should take precedence over environmental protection: The economy is a wholly owned subsidiary of the environment, not the other way around.

The elementary school in Clear Lake, Wisconsin is named Gaylord A. Nelson Educational Center.