The Museo Del Barrio, sometimes simply referred to as "El Museo," is a museum dedicated to primarily Puerto Rican Art. The institution was born out of East Harlem protests in the late 1960s that called for education in neighborhood public schools to include curricula that acknowledged and addressed the heritage of many of the families whose children attended these schools. A group of Central and East Harlem activists demanded for resources to be made available to students. In response, Superintendent Martin W. Frey of District 4 appointed Puerto Rican educator and activist Raphael Montaña Ortiz to create the educational materials necessary for this change. In response, Montaña Ortiz formed the idea to create a community-based museum that would supplement this necessity. A museum "del Barrio" (of the neighborhood) would be accessible to all ages, not just those attending the schools of District 4. East Harlem's primarily Puerto-Rican and Caribbean population needed to also benefit from this asset in their community.

The endeavor was funded by the Board of Education from 1969-1974, which enabled Montaña Ortiz to travel to Puerto Rico and make connections with local museums and anthropologists alongside Superintendent Martin W. Frey. Additionally, Montaña Ortiz visited museums across New York City to survey their collections of Puerto-Rican Art. Montaña Ortiz was conscious to involve the immediate community in discussions of the project, along with members of The Young Lords Political Party, The Real Great Society, and Marcos Dimas and Adrian Garcia who would later form the Art Worker's Coalition.

The museum was founded in a classroom of PS 125 at 425 West 123rd Street, where District 4's offices were also located. Montaña Ortiz said the following of the museum: "The cultural disenfranchisement I experience as a Puerto Rican has prompted me to seek a practical alternative to the orthodox museum, which fails to meet my needs for an authentic ethnic experience. To afford me and others to establish living connections with our own culture, I founded El Museo del Barrio."

El Museo del Barrio moved from the PS 125 to PS 206 and then subsequent storefronts in the vicinity. El Museo later moved to an old firehouse on 104th street, where it launched it's "Mobile Unit" that traveled to serve schools and events. Eventually, in 1977, El Museo settled in the Heckscher Building on 104th Street, where it occupied the ground floor. In this move, it joined the Cultural Institutions Group (CIG), an association of 23 cultural organizations housed in city-owned buildings. El Museo is the founding member of the Museum Mile.

The permanent collection of El Museo del Barrio spans over 800 years of Puerto-Rican, Latin American, Caribbean, and Latino Art. There are now around 6,500 pieces in the collection, and El Museo hosts a variety of temporary exhibitions on Puerto-Rican and Latin American Modern Art. Additionally, the institution is the site for many festivals, educational programs, and events. The most well known and widely attended festivity is the parade for Three Kings Day in January. The museum underwent a renovation and expansion in 2009 and another renovation of its theater from 2018 to 2019.

In 2012, an exhibition at now-defunct gallery Exit Art and a subsequent publication called "Alternative Histories" said that El Museo del Barrio went from alternative art space to a globally established museum. In El Museo's mission statement, it states the following: "To enhance the sense of identity, self-esteem and self-knowledge of the Caribbean and Latin American peoples by educating them in their artistic heritage and bringing art and artists into their communities."