Jaromir Krejcar (25 July 1895, Hundsheim, Austria - 5 October 1950, London) was a Czech functionalistic architect, student of Jan Kotera and member of Devetsil.

He collaborated with Czech structural engineer, Dr. Jaroslav Joseph Polivka on the internationally acclaimed Czech Pavilion at the Paris Exposition of 1937.

Krejcar was husband of journalist Milena Jesenska and father of Jana Krejcarova. After the communist coup in 1948 he went to exile to the United Kingdom.