Mary Loos (May 6, 1910 - October 11, 2004) was an actress, screenwriter and novelist.

Born in San Diego, California, she was the daughter of Dr. Clifford Loos, co-founder of the Ross-Loos Medical Clinic. She was the niece of screenwriter Anita Loos.

Loos died in Monterey, California due to complications following a stroke.