Marianne Yvonne Heemskerk (born 28 August 1944 in Rotterdam, South Holland) is a former butterfly swimmer from the Netherlands, who won the silver medal in the 100 m butterfly at the 1960 Summer Olympics in Rome, Italy.

She was also part of the 4 × 100 m medley relay team that finished fourth.

[2] Heemskerk broke the world record in the women's 200m butterfly on 12 June 1960 in Leipzig, East Germany.

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