Mattias Siimar

Mattias Siimar (born 3 February 1998) is an Estonian tennis player.

Siimar has a career high ATP singles ranking of 1036, achieved on 25 October 2021.

Playing for Estonia in Davis Cup, Siimar has a win–loss record of 5–6. His twin brother Kristofer Siimar is also a tennis player.

Participations: (5–6)

 * indicates the outcome of the Davis Cup match followed by the score, date, place of event, the zonal classification and its phase, and the court surface.