The new interactive site, called "Rethinking Guernica," was opened in the Spanish capital on Monday and gives internet users access to texts, manuscripts, letters, documents, catalogues, posters, audio and video recordings and other information on the painting.
Thanks to high-resolution imaging, the digital viewer can go on a virtual tour of the painting, zoom in on it and examine it in minute detail.
The museum said that the material was gathered from some 120 private and national collections, as well as from archives, libraries, institutes and art houses around the world, including the Picasso Museum in Paris' Pompidou Centre and Madrid's National Historical Archives.
The 27-square-metre "Guernica" was one of the most influential paintings of the 20th century. It was created after the Germans attacked the eponymous Basque town on April 26, 1937, during the Spanish Civil War.
The black, white and grey image shows deformed people and animals, suffering and fear. It was first shown at the World Expo in Paris in 1937.