Smithsonian Affiliations is a division of the Smithsonian Institution that establishes long-term partnerships with non-Smithsonian museums and educational and cultural organizations, in order to share collections, exhibitions and educational strategies and conduct joint research.
Partner organizations are known as "Smithsonian Affiliates" and are allowed to use the tag line "In Association with the Smithsonian Institution" and the approved Smithsonian Affiliations logo on their website, programming, and marketing material. Any 501(c)(3) nonprofit or publicly operated educational entity can apply to become a Smithsonian Affiliate.
The Smithsonian Affiliations program was established in 1996 by Smithsonian Secretary I. Michael Heyman with the approval of the Smithsonian Board of Regents, in response to several challenges the Institution faced at the time: a decrease in federal funding, limited storage space for expanding collections, and the need to make the Institution more reflective of the nation without operating additional museums outside of Washington, D.C.
In 1993, the Commission on the Future of the Smithsonian Institution introduced the first proposal for initiatives promoting strategic, collections-based partnerships at the Institution. The Commission, composed of 22 members appointed by the Smithsonian Board of Regents, was charged with examining the Institution's ability to uphold James Smithson's vision of an organization dedicated to "the increase and diffusion of knowledge" despite a changing society and increasing financial hardships. Of the four initiatives proposed by the Commission: Educate More of the Nation's People; Collections, Research and Exhibitions; Governance; and Assure the Future, two directly called for the creation of strategic partnerships and making artifacts in the collections accessible to other museums.
To Educate More of the Nation's People: "Build collaborative partnerships with other museums, research centers, and educational institutions throughout the nation."
Collections, Research and Exhibitions: "Shape a master plan for maintenance of the priceless collections, including the sharing of collections through long-term or permanent loans to partner institutions."
Significant emphasis was placed on the benefits that partnerships with outside museums would create for the Institution. By dispersing artifacts to museums in a responsible way, the Commission believed it, "could make the Institution more reflective of our nation… [as well as] address the problem of storing, curating, studying, and exhibiting the constantly growing collections."
In 1996, during his second year as Secretary, Heyman observed several challenges facing the Institution. Closely aligned with the announcements presented by the "Commission on the Future of the Smithsonian Institution" in 1993, Heyman was faced with the challenges of dwindling storage for expanding collections, decreasing funds, and the need to reinforce the Smithsonian's identity as the nation's museum. In addition, the Institution began to see increased interest from outside museums for partnerships and loans of artifacts that extended beyond standing practices. Although collaborative agreements in the form of traveling exhibitions, joint exhibition sponsorship, and loans had been entered in the past by different Smithsonian museums, no infrastructure existed to provide institution-wide oversight and coordination of such partnerships. Heyman responded to these challenges by creating the Smithsonian Affiliations program to oversee and manage collections-based partnerships with other museums. As stated by the minutes from the Smithsonian Board of Regents meeting housed in the Smithsonian Institution Archives, the program was formally approved by the Board of Regents on September 15, 1996.
Using the occasion of the Smithsonian Institution's 150th Anniversary, Smithsonian Affiliations was one of several outreach initiatives introduced by Heyman to expand the Institution's reach nationally.  In addition to the Affiliations program, the Institution became more accessible through its presence on the World Wide Web and through the largest traveling exhibition Smithsonian ever mounted, America's Smithsonian. Secretary Heyman made formal announcements about the Affiliations program while delivering opening remarks for the Smithsonian's 150th Birthday Party on the Mall and in a number of cities for the opening of America's Smithsonian:
"The Smithsonian of the future must provide access to its collections and its vast resources. There is no value in being just the largest if we do not share the Smithsonian with as many people as possible. It means making sure those who cannot travel to Washington can somehow experience and enjoy the Smithsonian." – Secretary I. Michael Heyman 
The program was received by museums across the country. The end of the fiscal year 1997 recognized 21 organizations as Affiliates. As of 2017, there are over 200 Affiliates.
Smithsonian Affiliations considers membership proposals from organizations that will advance the Smithsonian Institution's mission and strategic plan. Successful applicants are non-profit or publicly operated organizations whose missions are directed toward advancing research, knowledge, and education in science, history, and the arts. The guidelines of Smithsonian Affiliations establishes that the Smithsonian Institution maintain appropriate control over all collections loaned and that Affiliates cover all costs associated with borrowing and exhibiting objects. To qualify as an Affiliate, an organization must prove that it is able to properly care for, protect, and exhibit Smithsonian collections on a long-term basis. Strong applicants are organizations that are fiscally sound and capable of developing, installing, and evaluating professional exhibitions.
While serving as an Affiliate, organizations are required to grant Smithsonian Institution curators and personnel access to visit borrowed artifacts, provide the Smithsonian with reports and information necessary to monitor the state of the partnership, and uphold the integrity of the Board of Regents.
To become an Affiliate, organizations must submit an application package to Smithsonian Affiliations. Applicants are required to provide documentation that confirms IRS status as a 501(c)3 entity and a narrative detailing how the agreement will be mutually beneficial. Applications must also include a copy of the institution's mission statement, an organizational chart, an annual report, and a facilities report that follows the American Alliance of Museums format. Once approved, Affiliates are required to sign a Smithsonian Affiliations Agreement form and are assigned a National Outreach Manager to oversee loans and projects. All loan agreements are set for defined period of time.
Affiliate organizations participate in a number of professional training, outreach, and programming initiatives coordinated by the Smithsonian Affiliations office.
The Smithsonian Affiliations program supports, develops, and organizes a number of collaborative programs to promote education in science, art, history, and culture.
Affiliate organizations exchange ideas, professional research, and information about programming and exhibitions through a variety of activities including lecture, traveling exhibitions, workshops and reciprocal membership.
Affiliate organizations share research, exhibitions, and institutional updates through a variety of social media including the Smithsonian Affiliations website, the Affiliate Blog, the quarterly newsletter The Affiliate, the electronic newsletter E-Affiliate, YouTube, Flickr, Facebook and Twitter.
The following are representative samples of loans of artifacts, works of art, and scientific specimens loaned by the Smithsonian Institution to Smithsonian Affiliate organizations.
The National Museum of American History loaned the Pioneer (locomotive), a Civil War-era locomotive, to the B&O Railroad Museum in Baltimore, Maryland for the exhibit The War Came by Train.
Thomas Moran's painting The Grand Canyon of the Yellowstone, in the collection of the Smithsonian American Art Museum, was loaned to the Buffalo Bill Historical Center in Cody, Wyoming. The massive painting was on view from June 1, 2009 through October 31, 2009.
Artifacts from the Bisbee Mineral Collection at the National Museum of Natural History were loaned to the Bisbee Mining and Historical Museum in Bisbee, Arizona for use in the exhibit Digging In: Bisbee's Mineral Heritage.
Over 140 space objects, including the original Apollo 13 command module and the space suit worn by commanding astronaut James Lovell, were loaned to the Kansas Cosmosphere and Space Center in Hutchinson, Kansas.
The Durham Museum in Omaha, Nebraska borrowed 174 artifacts for the exhibit American Originals: Collections from the Smithsonian. Borrowed artifacts included the jacket worn by Bob Keeshan while filming the children's television series, Captain Kangaroo, a three-wheel Westcoaster Mailster used by the United States Postal Service in the 1960s, and two oil on canvass paintings of U.S. Supreme Court Justice Thurgood Marshall and Seneca Chief Red Jacket.
The National Museum of American History loaned Kermit the Frog to the National Mississippi River Museum and Aquarium in Dubuque, Iowa for use in the exhibit Toadally Frogs!
The Annmarie Sculpture Garden in Solomons, Maryland has over 20 sculptures on loan from the Hirshhorn Museum and Sculpture Garden.
The National Museum of Natural History loaned the Smithsonian Community Reef to the Putnam Museum and IMAX Theatre in Davenport, Iowa. The reef is composed of thousands of crocheted natural reef forms and was a highlight of the Sant Ocean Hall exhibit at the National Museum of Natural History .
"The Peoria Falcon," a sheet of copper stylized in the form of a falcon, was loaned to the Lakeview Museum of Arts and Sciences (now Peoria Riverfront Museum) in Peoria, Illinois by the National Museum of Natural History. The artifact was created during the Mississippian Period and excavated near Peoria, Illinois in the late 1850s.
The National Postal Museum loaned the Railway Post Office to the North Carolina Transportation Museum in Spencer, North Carolina.
The National Museum of Natural History loaned an 18-karat gold Monopoly set covered with precious gemstones to the Museum of American Finance in New York, New York. The board game was designed by artist Sidney Mobell.
The National Museum of Natural History loaned the skeleton of the racehorse, "Lexington," to the International Museum of the Horse in Lexington, Kentucky
The top hat worn by president Abraham Lincoln on the night of his assassination was loaned to the Blackhawk Museum in Danville, California by the National Museum of American History.
The exhibit, Smithsonian Expeditions: Exploring Latin American and the Caribbean at the Miami Museum of Science, borrowed several artifacts from the National Museum of Natural History including painted gourds and a 5-foot tall monolith from the Nicaraguan island of Momotombito.
The Historic Arkansas Museum borrowed over 40 artifacts from the National Museum of the American Indian for the exhibit We Walk in Two Worlds: The Caddo, Osage and Quapaw in Arkansas.
The Smithsonian American Art Museum loaned three José Campeche paintings to the Museo de Arte de Puerto Rico in San Juan, Puerto Rico.
The Senator John Heinz History Center in Pittsburgh, Pennsylvania has on loan from the National Museum of American History a Bantam Jeep and a piece of the original Star Spangled Banner Flag.
Yokohama prints from the Freer Gallery of Art and the Arthur M. Sackler Gallery were loaned to the Japanese American National Museum in Los Angeles, California for the exhibit Japan After Perry: Views of Yokohama and Meiji Japan.
The National Postal Museum loaned stamp designs and drawings created by president Franklin D. Roosevelt to the Blackhawk Museum in Danville, California.