Renée Hložek (born 15 November 1983) is a South African cosmologist, Professor of Astronomy & Astrophysics at the Dunlap Institute for Astronomy & Astrophysics at the University of Toronto, and an Azrieli Global Scholar within the Canadian Institute for Advanced Research. She studies the cosmic microwave background, Type Ia supernova and baryon acoustic oscillations. She is a Sloan Research Fellow in 2020. Hložek identifies as bisexual.