Rosa Díez González (born May 27, 1952 in Güeñes, Biscay, Spain) is a Spanish politician. She is a former Member of the European Parliament for the PSOE ("Partido Socialista Obrero Español" or Spanish Socialist Workers' Party), integrated in the Party of European Socialists.
In 2007 she gave up her seat and left the PSOE due to strong disagreement on what she perceived to be the Socialists' drift on individual liberties, ETA, and more. Subsequently she founded a new political party, UPyD ("Unión, Progreso y Democracia" or Union, Progress and Democracy), based on an already existing movement. In 2008 and 2011, she was elected to the Congress of Deputies (Spain) representing Madrid district.