Hendrika Wilhelmina "Rie" Mastenbroek (26 February 1919 – 6 November 2003) was a Dutch swimmer and a triple Olympic champion.

In 1934, Mastenbroek won three gold medals and a silver at the European Championships.

(Senff missed a turning point and had to swim back before completing the last 50 m. She nevertheless beat Mastenbroek thanks to an outstanding last leg.

)[1] The following year she became a swimming instructor, thereby losing her amateur status and becoming ineligible for competition.

After her death, Stichting Aquarius named the Rie Mastenbroek Trophy after her.