Gaba was born in 1961 in Cotonou, Benin. He studied at the Rijksakademie voor Beeldende Kunsten in Amsterdam in 1996-97.
It was at the Rijksmuseum, Leiden, in 1997 that Gaba inaugurated his major work, the Museum of Contemporary African Art, a project in which the artist installed 12 'rooms' of a nomadic museum in various institutions over a period of five years, culminating with his presentation of a 'Humanist Space' at Documenta 11. Other 'rooms' include the Museum Restaurant (shown at W139, Amsterdam, in 1999), the Games Room (shown in Besançon, France, in 1999 and in Brussels and Gent in 2000), the Library of the Museum (Witte de With, 2001, and published in 2001), and the Salon (Palais de Tokyo, Paris, 2002).
The Museum of Contemporary African Art (1997-2002) was acquired by Tate and exhibited at Tate Modern, London, in 2013. The Library of the Museum was donated by Gaba to the city of Cotonou as part of his project Musée de l'Art de la Vie Active (MAVA). Gaba's survey exhibition Museum for Contemporary African Art & More showed at the Museum de Paviljoens in Almere, the Netherlands; the Kunsthalle Fridericianum in Kassel, Germany; and the Centro Atlántico de Arte Moderno in Las Palmas, Canary Islands, in 2009/10.
Notable group shows include Their Own Harlems at The Studio Museum in Harlem (2017); Afrique Capitales at La Villette in Paris (2017); Making Africa: A Continent of Contemporary Design at the Vitra Design Museum, Weil am Rhein (2015); Atopolis, Mons 2015 - European Capital of Culture; Liberated Subjects: Present Tense, Foundation De 11 Lijnen, Oudenburg (2015); The Theatre of the World, Museo Tamayo, Mexico (2014); When Attitudes Became Form Become Attitudes: A Restoration / A Remake / A Rejuvenation / A Rebellion, CCA Wattis Institute for Contemporary Arts, San Francisco; Museum of Contemporary Art, Detroit (2013); Benin Biennale (2012); La Triennale - Intense Proximity, Palais de Tokyo, Paris (2012); The Global Contemporary: Art Worlds after 1989 at ZKM Center for Art and Media Karlsruhe, Germany (2011); Touched, the 2010 Liverpool Biennale; Port City at Greenland Street Gallery, Liverpool (2008); Africa Remix (2004-2007) and, in 2006, the São Paolo, Gwangju, Sydney and Havana biennales.