Jānis Dimza (1 November 1906, Ipiķi parish – c. 1942) was a Latvian decathlete.

He placed fourth at the European Championships in 1934, and challenged for medals at the Olympic Games in 1932 until he injured himself in the pole vault.

[4] He had scored 7789 points in that event in 1931,[1][5] and was one of many favorites in what was expected to be a close competition.

[5] Dimza returned to competition once his leg healed, placing 4th at the 1934 European Championships in Turin.

[6] He died in a Soviet prison camp during World War II.