Reinertsen is a surname. Notable people with the surname include:
Emma May Alexander Reinertsen (1853–1920), American writer, social reformer Espen Reinertsen (born 1979), Norwegian saxophonist, flutist, composer, and music producer Jon Reinertsen (born 1946), Norwegian handball player Sarah Reinertsen (born 1975), American paratriathlete Stein Reinertsen (born 1960), Norwegian Lutheran bishop Terje Reinertsen (born 1987), Norwegian footballer Trond Reinertsen (born 1945), Norwegian economist and businessman