Maggy Breittmayer (2 September 1888 – 6 May 1961) was a Swiss violinist and academic.
She was born in Geneva, daughter of Henri Jean Breittmayer, an assistant judge and state councillor, and his wife Olga Amélie née Soltermann.
In 1909, obtaining a scholarship from the Association of Swiss Musicians, she studied in Berlin with Carl Flesch.
She began a career as a concert violinist, playing in Switzerland, Paris, the Netherlands and Berlin, including works by contemporary Swiss composers Marguerite Roesgen-Champion and Émile Jaques-Dalcroze.
She resumed teaching at Geneva Conservatory; in 1918 she was a founder member of the Orchestre de la Suisse Romande.