Timothy E. Wirth (September 22, 1939-) is a former United States Senator from Colorado. Wirth, a Democrat, was a member of the House from 1975 to 1987 and was elected to the Senate in 1986, serving one term there before stepping down. He was Undersecretary of State for Global Affairs during the Clinton Administration.
In the State Department, he worked with Vice President Al Gore on global environmental and population issues, supporting the administration's views on global warming (see "the science is settled"). A supporter of the proposed Kyoto Protocol, Wirth announced the US's commitment to legally binding limits on greenhouse gas emissions.
Wirth left government to head the United Nations Foundation, begun in 1997 by media mogul Ted Turner with a pledge of $1 billion.
Wirth is a graduate of Phillips Exeter Academy and Harvard University and holds a PhD from Stanford University. He has also served as a member of the Harvard Board of Overseers.
Wirth is married to Wren Winslow Wirth, the President of the Winslow Foundation; together they have two children, Christopher and Kelsey Wirth. Their daughter, Kelsey Wirth, is the co-founder of the orthodontic production company Align Technology, makers of Invisalign. His nephew, Peter Wirth, was elected in 2004 to the New Mexico State Legislature.