Masako Seki (関 正子, Seki Masako, 1941 or 1942 – September 18, 2019) was an international table tennis player from Japan.

From 1961 to 1965 she won several medals in singles, doubles, and team events in the World Table Tennis Championships and in the Asian Table Tennis Championships.

[1] Her eight World Championship medals[2][3] included four gold medals; two in team event, one in the doubles with Kimiyo Matsuzaki at the 1963 World Table Tennis Championships and one in the mixed doubles with Koji Kimura at the 1965 World Table Tennis Championships.

[4][5] She died at the age of 77 on September 18, 2019.

This biographical article relating to a Japanese table tennis figure is a stub.