María Luz Casal Paz (Spanish pronunciation: [luθ kaˈsal]; born 11 November 1958) is a Spanish rock singer. She grew up in Boimorto, Galicia (Spain), took singing, piano and ballet classes, and moved to Madrid to pursue a career as a musician.

She became famous in the early 1980s, and remained an important figure in Spanish pop music all through said decade and beyond, with her sound gradually maturing towards soft adult pop. She recorded a cover version of Étienne Daho's French language song "Duel au Soleil" in Spanish called "Un nuevo día brillará", which became a hit song. Since the beginning of her career, she has sold over five million albums.

In 1992, she enjoyed great success with her appearance in the soundtrack of Pedro Almodóvar's acclaimed film High Heels singing Agustín Lara's theme "Piensa en mí".

In January 2007, Luz Casal was diagnosed with breast cancer and underwent an operation at the Ruber Clinic in Madrid, seven months later, she revealed to the Spanish media that she had overcome her disease. More recently in May 2010, she announced that she had been diagnosed with cancer in her other breast and had to cancel her current tour to be operated on.

Her middle name, Luz, means "light" in Spanish.