The Mathers Museum Collections consist of over 30,000 objects and 10,000 photographs representing cultures from each of the world's inhabited continents. These materials have been collected and curated to serve the museum's primary mission as a teaching museum within a university setting. The ethnology collections strengths include traditional musical instruments, photographs of Native Americans and the Bloomington community, Inupiaq and Yupik Eskimo materials, and Pawnee material culture, among others.

African Collections. The museum holds several significant collections of African materials. In all, the collection contains over 2,900 pieces representing countries throughout West, East, and Central Africa. The strongest collections come from: the Tetela of eastern Zaire, obtained by John White in the late 1920s and early 1930s; the Hausa and Yoruba of Nigeria, collected by Arnold Rubin, former professor of Art History at UCLA; the Hausa of Nigeria, collected by renowned art historian Roy Sieber; and a large number of musical instruments collected throughout Africa by pioneering ethnomusicologist, Laura Boulton. Other African collections include materials from Angola, Cameroon, Kenya, Cote d'Ivoire, Ethiopia, Gabon, Guinea, Liberia, Mali, Sierre Leone, Uganda, and Zambia.

Asian/Pacific-Oceania Collections. The museum holds several significant collections of Asian materials from Japan, Burma, Pakistan, and Tibet. The Pacific/Oceania collections include materials from Java, Philippines, Malaysia, Papua New Guinea, and Palau.

North American Euro American Collections. The museum holds several significant collections of American/Indiana historical material. These include artifacts documenting home textile industries, carpentry, stoneworking, and the business records of a Bedford, Indiana, blacksmith shop, ca. 1930-1960. The Museum also has several collections of American Folk Art. In addition, the Mathers Museum holds several collections of historical photographs. These include images by Charles G. Shaw of Bloomington, ca. 1900-1935, and the Elizabeth Bridgwaters and John Drake collections documenting Black community life in Bloomington, ca. 1900-1990. The Mathers Museum also has a small collection of railroad photographs.

North American Native American Collections. The museum collections from native North America consist of approximately 8,000 objects. Most of the collections represent the early to mid-20th century, although there are some older pieces. The single largest collection was made at Point Barrow, Alaska in the 1930s, documenting the lives of Inupiaq Eskimo groups. Another significant tribal collection is the Ellison Collection of Pawnee Indian materials. Other important collections document Florida Seminole groups, and several of the Southwestern Pueblos and the Navajo. The Museum also holds over 8,000 photographs of American Indians from the Wanamaker Collection made between 1908-1923.

Central and South American Collections. The Central and South American collections in the museum consist of approximately 3,000 artifacts. Most of the materials date to the mid-20th century, but some are considerably older. Cultures of Mexico, Guatemala, Brazil, Surinam, Colombia, and Peru account for most of the ethnographic holdings, although other countries are represented. Topical strengths include traditional costumes, musical instruments, folk paintings, and ritual artifacts. Among the latter are items representing several Afro-Latin American folk religions. In addition to these 20th-century artifacts, the Museum has a small collection of Spanish Colonial materials, mostly from Peru. There are also small archaeological collections from Peru (ceramics and textiles) and Central America (ceramics and ground stone).

Ethnomusicological Collections. The museum's collection of over 2,000 ethnomusicology items is one of the largest such collections in the country, and includes materials from all continents. Two important collections, the Laura Boulton Collection and the Georg Herzog-Hans van Hornbostel Collection, make up its core. Dozens of other acquisitions from the earliest days of the Museum through to the present add to the range and depth of the collection.

Photography Collections. The museum has several significant collections of photographic materials. These include over 8,000 images of the Wanamaker Collection of Native American photographs, the Shaw-Starkes photographs of Bloomington, ca. 1900-1935, and the Elizabeth Bridgwaters and John Drake collections documenting the African-American Community in Bloomington, ca. 1900-1990. In addition, there are several historic sets of lantern slides representing scenes from around the world. The artifact collections include several historic/antique cameras and examples of home film and print processing technology.

Textiles Collections. The textile collection, featuring over 400 pieces, contains a range of materials from Southern Indiana quilts to Tibetan thankas. This sub-collection also contains examples of the skill and variety in traditional textile work: Southeast Asian batik and ikat, Andean in-loom embroidery, African resist dying and embroidery, Sea Island Gullah quilts, Middle-Eastern tapestry and carpet-weaving, Seminole patchwork, and Pueblo and Navajo upright and belt loom textiles.