Stanisława Walasiewicz (April 11, 1911 – December 4, 1980) was a Polish-American athlete.

Walasiewicz was born in Rypin , Poland, but her family emigrated to the United States when she was two. She repeatedly attempted to obtain US-citizenship, but this was not granted it until she appeared to be a very quick 100 m. runner. Accepting the citizenship would however affect Walasiewicz's amateur status, and she decided to run for Poland at the 1932 Summer Olympics.

In both the heats and the semi-finals of the 100 m., Walasiewicz equalled the current world record of 11.9 seconds, a feat she repeated in the final, which she won. The same day, she also finished 6th out of 9 in the discus throw event.

While still not a US citizen, Walasiewicz did participate in, and won, numerous American national championships, usually under the name of Stella Walsh. In the 1936 Olympics in Berlin, she attempted to defend her Olympic title, but, as the World Record holder by now, she was beaten to the title by Helen Stephens.

She married in 1947 and was finally granted citizenship as Stella Walsh Olson. She won her last US title at age forty, in 1951.

Walsh became involved in an armed robbery in Cleveland, Ohio in 1980 and was killed. An autopsy showed that she was in fact intersex, with externally female genitals, but with testicles as well. Had this been known, her career would have been quite different because International Association of Athletics Federations (IAAF) regulations prohibited participation of intersexed people like Walasiewicz in women's events until 1992, when it had been proven that they would not have benefits over other women.