The Universal Forum of Cultures (Catalan: Fòrum de les Cultures) was an international event which took place in Barcelona, Catalonia, Spain from May 9 to September 26, 2004.

The 2004 Universal Forum of Cultures was organized by Barcelona's local council, the regional government (the Generalitat de Catalunya), the Spanish National Government and UNESCO. It was conceived by its prime mover (Pascual Maragall, then Mayor of Barcelona) as a way of promoting the city's burgeoning tourist industry in the wake of the 1992 Olympic Games.

The official aims of the 2004 Universal Forum of Cultures included support for peace, sustainable development, human rights and respect for diversity.

The event was controversial, with critics pointing to the $2.3 billion price tag and commercial sponsorship by multinationals (ENDESA, Nestlé, Coca-Cola, Telefonica, and Indra) with dubious reputations in the Third World. Several groups also criticised the massive property and coastline destruction involved in building the Forum site. In addition, many NGOs, including Greenpeace and Amnesty, withdrew from the Forum project in protest. This may explain why the Forum fell so far short of its projected attendance figures for the 141-day event. The forecasts were progressively scaled back from 25 million at the planning stage, to 7 million and then 5 million during the event. The official final attendance figure was around 3.5 million, although even this figure is hotly disputed.

The 2007 Universal Forum of Cultures will be held in Monterrey, Mexico.