Satu Maijastiina Hassi (born 3 June 1951) is a Finnish politician, and Member of the European Parliament for the Green League. She served as the Minister of Environment and Development Co-Operation in Paavo Lipponen's second cabinet between 15 April 1999 and 31 May 2002. In accordance with her party's position on the issue, she quit the cabinet in protest of the government's decision to build a fifth nuclear power plant in Finland. Hassi served as the leader of her party between 1999 and 2001.