Diane Edith Watson (born November 12, 1933) is a former US Representative for California's 33rd congressional district, serving from 2003 until 2011. She is a member of the Democratic Party. The district is located entirely in Los Angeles County and includes much of Central Los Angeles, as well as such wealthy neighborhoods as Los Feliz.
A native of Los Angeles, Watson is a graduate of the University of California, Los Angeles, and also holds degrees from California State University, Los Angeles and Claremont Graduate University. She worked as a psychologist, professor, and health occupation specialist before serving as a member of the Los Angeles Unified School Board (1975–78). She was a member of the California Senate from 1978 to 1998, and the US Ambassador to Micronesia from 1999 to 2000.