Jan Kotera (18 December 1871 - 17 April 1923) was a Czech architect, artist and interior designer, and one of the key figures of modern architecture in Bohemia.

Kotera was born in Brno, the largest city in Moravia, to a Czech father and German-speaking mother. He studied architecture in Vienna during the waning days of the Austro-Hungarian Empire under the Viennese master Otto Wagner.

Kotera returned to Prague in 1897 to help found a dynamic movement of Czech nationalist artists and architects centered around the Manes Union of Fine Arts. Strongly influenced by the work of the Vienna Secession, his work bridged late nineteenth-century architectural design and early modernism. Kotera collaborated with Czech sculptors Jan Stursa, Stanislav Sucharda, and Stanislav's son Vojtech Sucharda on a number of buildings.

As a teacher, Kotera trained a generation of Czech architects, including Josef Gocar, who would bring Czech modernism to its pinnacle in the years leading up to the Nazi occupation in 1939.