Janet Mary Grieve ONZM, also known as Janet Bradford-Grieve and Janet Bradford, is a New Zealand biological oceanographer, born in 1940. She is researcher emerita at the National Institute of Water and Atmospheric Research in Wellington. She has researched extensively on marine taxonomy and biological productivity. She was president of both the New Zealand Association of Scientists (1998–2000) and the World Association of Copepodologists (2008–11).