Gaja is a given name. The name Gaja comes from the Greek word "gaia" which means Earth.
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