Gaja is a given name. Notable people with the name include:
- Gaja Alaga (1924–1988), Croatian theoretical physicist
- Gaja Dabić (c. 1780 – after 1847), duke and leading commander in the Serbian Revolution
- Gaja Grzegorzewska (born 1980), Polish novelist
- Gaja Natlačen (born 1997), Slovenian swimmer
- Gaja Prestor (born 2000), Slovenian singer