SDSU is an acronym that may refer to:
- Universities in the United States of America:
- San Diego State University in San Diego, California
- South Dakota State University in Brookings, South Dakota
- Television series:
- Sit Down, Shut Up, an American television series
- Sit Down, Shut Up, an Australian television series
- Transportation:
- SDSU Transit Center, a station served by the San Diego Trolley on the San Diego State University campus