Gerrit Thomas Rietveld (June 24th, 1888 - June 26th, 1964) was a Dutch furniture designer and architect. In 1916, Rietveld started his own furniture factory, while studying architecture. Rietveld designed the Red and Blue Chair in 1917, but changed its colours to the familiar style in 1918 after he became influenced by the 'De Stijl' movement, of which he became a member in 1919, the same year in which he became an architect.

In 1924 he designed his first building the Rietveld Schroder House in close collaboration with the owner Rutger Jan Schimmelpenninck. The house is small. The design is conventional on the ground floor, but radical on the top floor, being entirely open plan, with no fixed walls. The design seems like a three dimensional realisation of a Mondrian painting. The house in Utrecht is a UNESCO World Heritage Site since 2000.

Rietveld broke with the 'De Stijl' movement in 1928 and switched to the Nieuwe Zakelijkheid. The same year he joined the Congres Internationaux d'Architecture Moderne.