Jan Peter Toennies (born 3 May 1930) is a German-American scientist.
He was born in Philadelphia, Pennsylvania on 3 May 1930 to German immigrant parents.
He graduated from Lower Merion High School, outside of Philadelphia, in 1948.
He went on to Amherst College, where he finished with a BA in 1952, and to Brown University, where he received a PhD in chemistry in 1957.
During graduate school he was a Fulbright student in Göttingen 1953–1954.