William Slattery Lieberman (February 14, 1923 – May 31, 2005) was an American museum curator.
Lieberman's curatorial career began at the Museum of Modern Art (MoMA) in 1943. In 1979, Lieberman moved to The Metropolitan Museum of Art (The Met) as chairman of the department of 20th-century art.
Lieberman was known for his detailed visual memory and for pairing works by different artists in his installations. At the time of his death, he was a special consultant for the museum