Olga Taussky-Todd (August 30, 1906, Olomouc, then Austria–Hungary – October 7, 1995, Pasadena, California) was a Czech-American mathematician.
She worked first in algebraic number theory, with a doctorate at the University of Vienna supervised by Philipp Furtwängler. During that time in Vienna she also attended the meetings of the Vienna Circle. Later, she started to use matrices to analyze vibrations of airplanes during World War II, at the National Physical Laboratory in the United Kingdom. She became the torchbearer for matrix theory.
In 1938 she married another mathematician, John Todd.
In 1945 the Todds immigrated to the United States and worked for the National Bureau of Standards. In 1957 they joined the faculty of California Institute of Technology in Pasadena, California.
She was a Fellow of the AAAS, a Noether Lecturer and a recipient of the Austrian Cross of Honour for Science and Art. She also supervised Caltech's first female Ph.D. in Math, Lorraine Foster.