[10] Its first assets were transferred from the university and the Ontario Department of Education,[8] coming from its predecessor, the Museum of Natural History and Fine Arts at the Toronto Normal School.

The original building was constructed on the western edge of the property along the university's Philosopher's Walk, with its main entrance facing out onto Bloor Street housing five separate museums of the following fields: Archaeology, Palaeontology, Mineralogy, Zoology, and Geology.

[18][19] The second major addition to the museum was the Queen Elizabeth II Terrace Galleries on the north side of the building and a curatorial centre built on the south, which started in 1978 and was completed in 1984.

[22] The campaign aimed not only to raise annual visitor attendance from 750,000 to between 1.4 and 1.6 million,[24] but also to generate additional funding opportunities to support the museum's research, conservation, galleries and educational public programs.

[30][31] Designed by Toronto architects Frank Darling and John A. Pearson,[32] the architectural style of the original building (now the western wing) is a synthesis of Italianate and Neo-Romanesque.

Writing in the Journal of the Royal Architectural Institute of Canada in 1933, A. S. Mathers said of the expansion:[34] The interior of the building is a surprise and a pleasant one; the somewhat complicated ornament of the façade is forgotten and a plan on the grand manner unfolds itself.

[40] Replacing the Queen Elizabeth II Terrace Galleries was the controversial "Michael Lee-Chin Crystal", a multimillion-dollar expansion to the museum designed by Daniel Libeskind, including a new sliding door entrance on Bloor Street, first opened in 2007.

On its opening, Globe and Mail architecture critic Lisa Rochon complained that "the new ROM rages at the world", was oppressive, angsty and hellish,[45] while others—perhaps championed by her Toronto Star counterpart, Christopher Hume—hailed it as a monument.

[50] The lobby is overlooked by balconies and flanked by the J. P. Driscoll Family Stair of Wonders and the Spirit House, an interstitial space formed by the intersection of the east and west crystals.

[52] Within the Crystal there is a gift shop, C5 restaurant lounge (closed until further notice), a cafeteria, seven additional galleries and Canada's largest temporary exhibition hall in a museum.

[55] Although a two-layer cladding system was incorporated into the design of the Crystal to prevent the formation of dangerous snow loads on the structure, past architectural creations of Daniel Libeskind (including the Denver Art Museum) have also suffered from weather-related complications.

The space was inspired by the ROM's collections and enabled children to participate in interactive activities involving touchable artifacts and specimens, costumes, digging for dinosaur bones and examining fossils and meteorites.

[61] The Patrick and Barbara Keenan Family Gallery of Hands-On Biodiversity introduces visitors to the complicated relationships, which occur among all living things in a fun and interactive space.

Mossy frogs, a touchable shark jaw, snakeskin, and a replica fox's den are some of the objects that connect young visitors to the diversity and interdependence of plants and animals.

The display features examples of the regions and the efforts by the Ontario Ministry of Northern Development, Mines, Natural Resources and Forestry to maintain and restore the tallgrass prairies and savannas.

The Royal Ontario Museum purchased a beached blue whale off the coast of Newfoundland at Trout River and displayed its skeleton and heart as a ROM-original travelling exhibit until 4 September 2017.

[79] The Teck Suite of Galleries: Earth's Treasures features almost 3,000 specimens of minerals, gems, meteorites and rocks ranging from 4.5 billion years ago to the present.

[86] The ROM also has a Zuul crurivastator skeleton from the Judith River Formation in Montana in its dinosaur collection, which is one of the most complete examples of an ankylosaurid specimen ever found.

The Sir Christopher Ondaatje South Asian Gallery holds a diverse collection of objects such as decorative art, armour and sculptures that represents the culture of Indian subcontinent.

[92]The Wirth Gallery of the Middle East explores civilizations from the Palaeolithic Age to 1900 AD found within the Fertile Crescent, which stretches from the Eastern Mediterranean and Persia (Iran) and Mesopotamia (Iraq) to the Arabian Peninsula and the Levant (Lebanon and Israel).

It has the largest collection of classical antiquities in Canada, displaying more than 500 objects that range from marble or painted portraits of historical figures to Roman jewellery.

[97] The same space holds the Joey and Toby Tanenbaum Gallery of Byzantium, covering the history of the Byzantine Empire from AD 330 to 1453, during which crucial changes took place in early eastern Christianity.

There are over 230 artifacts that relate to the dedication of Constantinople,[98] the fall of the Western Roman Empire, the Medieval Crusades and the conquest by the Ottoman Turks—items such as jewellery, glasswork and coins help to illustrate the vast history of modern-day Istanbul.

[104] The Gallery of the Bronze Age Aegean features over 100 objects that include examples from the Cycladic, Minoan, Mycenaean and Geometric periods of Ancient Greece.

There is also a rotating display of contemporary Native art, an area dedicated to the works of pioneer artist Paul Kane and a theatre devoted to traditional storytelling.

[126] Furniture, ceramics, metalwork, printing technology, painting and decorative arts, dating from the 3rd to 20th centuries AD, illustrate the many accomplishments to Korean culture.

The influence of Buddhism on Korean culture is portrayed with two statues, the first being a śarīra casket, which originated in India and were made to enshrine the remains of a Buddha or enlightened masters[127] and the second of a tomb guardian.

[136] The piece was one of 12 tazzas that made up the Aldobrandini Tazze, a set of Renaissance-era cups that featured the first 12 Roman emperors whose lives are described in the AD 121 publication The Twelve Caesars.

A main goal of the program is to give the museum the power to engage, share and inspire a greater diversity of visitors by trying to break through economic and social barriers.

[138] Partners include United Way of Greater Toronto, Boys & Girls Clubs of Canada, The Hospital for Sick Children and the Centre for Addiction and Mental Health (CAMH).