Jean Marie Octave Constant Washer (French pronunciation: [ʒɑ̃ waʃe]; 22 August 1894 – 23 March 1972) was a Belgian tennis player successful in the 1920s.

The correspondent from Le Sport universel illustré summed up the Belgian by saying "Washer is one of the most conscientious players in existence.

[4] The article went on to describe the final and said Washer had a "very good forehand" and made a "better showing than the result seems to indicate, because he obliged the great Tilden to work hard".

"The Belgian attacked with magnificent brilliance" and his service "began to annoy Cochet too".

Washer reached the semifinals of Roland Garros in 1925, beating Cochet in the quarter finals.