Rosa María Díez González (born 27 May 1952) is a Spanish politician from Union, Progress and Democracy, UPyD deputy in the Congress of Deputies from 2008 to 2016.
She was 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 particularly due to disagreement on what she perceived to be the Socialists' drift on individual liberties.
She founded a new political party called Unión, Progreso y Democracia in Spanish and Union, Progress and Democracy in English (UPyD), based on the existing movement of Basque citizens against ETA violence ¡Basta Ya!. In 2008 and 2011, she was elected to the Congress of Deputies (Spain) representing Madrid district. In the Spanish General Elections of 2011, she was re-elected and her party was the fourth most voted party in Spain.
Díez personally advocates for lower public wages. Subsequently, and although she was the UPyD spokesperson on five committees, she was only paid for one of them.
On 24 May 2015, she announced she would not seek reelection as spokesperson of UPyD due to the party's poor performance in the regional and municipal elections.