Theodor Schneider (born May 7, 1911 in Frankfurt am Main; died October 31, 1988, Freiburg im Breisgau) was a German mathematician, best known for providing proof of what is now known as the Gelfond–Schneider theorem in 1935.
Schneider studied from 1929 to 34 in Frankfurt; he solved Hilbert's 7th problem in his PhD thesis, which then came to be known as the Gelfond–Schneider theorem. Later he became an assistant to Carl Ludwig Siegel in Göttingen, where he stayed until 1953. Then he became a professor in Erlangen (1953–59) and finally until his retirement in Freiburg (1959–1976). During his time in Freiburg he also served as the director of the Mathematical Research Institute of Oberwolfach from 1959 to 1963.