Pepe Serra, director of the National Art Museum of Catalonia where the exhibition opens on Friday, said it highlights that Gala had an important, active role in the surrealist artist's "creative, life-long project."
"Gala Salvador Dalí" gathers more than 300 elements from 18 museums and collections like the Georges Pompidou Centre in Paris or the Salvador Dali Museum in Florida.
It includes Dalí's paintings and sketches of Gala, as well as items of their private life like letters, postcards, photos, clothes and personal objects.
Born in 1894 into a family of intellectuals from Kazan, Russia, she spent her childhood in Moscow.
She settled in Switzerland where she met the French poet Paul Eluard, with whom she moved to Paris and had a daughter.
Gala was the mistress of German painter Max Ernst and the muse of photographers such as Britain's Cecil Beaton.
"Gala has much more of a role in (Dalí's) work than what is attributed to her," said Estrella de Diego, curator of the exhibition.
1944 portrait of Gala Dalí by Salvador Dalí, in Figueres. Photo: Wikimedia