UCD can refer to:
Education
- University College Dublin, Irish university
- University College Dublin A.F.C., the university's association football club
- University College Dublin RFC, the university's rugby union club
- UCD GAA, the university Gaelic games club
- University of California, Davis
Science and technology
- User-centered design
- Use case diagram
- Urine collection device
- Ultra compact dwarf galaxy
- Unicode Character Database
Other
- Unión Cívica Democrática
- Union of the Democratic Centre (disambiguation), party name in various countries
- Union of the Democratic Centre (Spain)
- Union of the Democratic Centre (Argentina)