Semisi is a given name and surname. Notable people with the name include:
Semisi Fakahau (1948−2022), Tongan politician Semisi Fonua (1911–1968), Tongan noble Semisi Masirewa (born 1992), Fijian rugby union player Semisi Naevo (born 1975), Fijian rugby union player Semisi Paea (born 1999), Tongan rugby union player Semisi Sika (born 1968), Tongan politician Semisi Tapueluelu (born 1949), Tongan politician Semisi Taulava (born 1983), Tongan rugby union player Semisi Telefoni (born 1982), New Zealand-born Tongan rugby union player Semisi Tora (born 1979), Fijian rugby league player Semisi Tupou (born 1999), Australian rugby union player Peniuto Semisi (), Tokelauan politician