John B. Frizzell (born in Kingston, Ontario) is a Canadian screenwriter and film producer. After several years writing, directing and co-producing the documentary series A Different Understanding for TVOntario, Frizzell joined partners Niv Fichman, Barbara Willis Sweete and Larry Weinstein to found the Canadian production company Rhombus Media. He left Rhombus in the mid-eighties to pursue a career in writing.