The Prince of Asturias prize jury hailed Leibovitz, 63, as "one of the driving forces of world photojournalism", in a statement naming her the winner of its Communication and Humanities award.
"She has achieved recognition for her snapshots and portraits which reflect an era of politics, literature, film, music and sport through its leading figures."
Connecticut-born Leibovitz is one of the world's top portrait photographers, with snaps of the powerful and famous that have made the front pages of magazines such as Vogue, Vanity Fair and Rolling Stone, where she started out in 1970.
She snapped Richard Nixon as he quit the White House and George W. Bush's government as it met shortly after the attacks of September 11th, 2001, as well as President Barack Obama and his family.
Her imaginative staged compositions have marked her out, such as those of the Beatle singer Lennon and Ono curled up naked together or of US sprinter Carl Lewis in high heels.
One of her best-known magazine cover photos depicted the actress Demi Moore caressing her own belly, naked and seven months pregnant in 1991.
The Prince of Asturias awards are given in the fields of arts, communication and humanities, scientific and technical research, social science, letters, international cooperation, international understanding and sport.
Named after Crown Prince Felipe, the €50,000 prizes are presented in the northern Spanish city of Oviedo, capital of the northern Asturias region, in a ceremony broadcast live on Spanish television in October.