The Mill Mountain Zoo is a zoo located atop Mill Mountain in Roanoke, Virginia, United States. When it opened in 1952, the zoo was operated by the City of Roanoke. In 1976, the city turned its operation over to the Roanoke Jaycees. The Jaycees operated the zoo until 1988 when its operation was handed over to the non-profit Blue Ridge Zoological Society (BRZS). The BRZS still serves as the operator and fund raiser for the zoo.

With its location atop Mill Mountain not being conducive to a major expansion, a proposal was developed in 1984 to relocate the zoo to a 400-acre (160 ha) tract adjacent to the Blue Ridge Parkway to be called the Blue Ridge Zoo. This proposal was later abandoned in favor of the development of Virginia's Explore Park at that location. After the failed relocation proposal, the Blue Ridge Zoological Society voted in 1988 to keep the zoo permanently atop Mill Mountain. As part of this decision, a 10-year master plan, called Zoo 2001, was completed in 1991, with some of its suggestions implemented over the course of the next decade.

The zoo was accredited by the Association of Zoos and Aquariums (AZA) from 1995 to 2016. The zoo lost accreditation due to funding instability, and the "AZA noted the facility itself and the care for animals still operates at a high standard". Mill Mountain Zoo continues to be accredited by the Zoological Association of America (ZAA).

In June 2021, the zoo completed its largest capital project in three decades and added a black bear, heritage goats, hogs, and other animals.

• New holding/quarantine building (houses new animals and the birds during the winter) – not accessible to the public
• New animal clinic – not accessible to the public
• Red Wolf Exhibit
• Black Bear Exhibit
• Interactive Aviary
• Reptile House

The following are some of the more notable animals and attractions that have been at the zoo:

• Frump Frump was an African elephant donated to the zoo from a passing circus in 1970. Although she would die just a few months after being placed in the zoo, a record 107,000 visitors came, with many making the trip specifically to see her.
• Ruby was a Siberian tiger. She was donated to the zoo by law enforcement officers who found her being kept illegally as a pet in Danville, Virginia. Ruby was at the zoo from November 1988 until her death on December 10, 2006. Her habitat has since been converted to a wolf habitat.
• Oops is a Japanese macaque who escaped her cage in July 2006. Her escape was covered nationwide before she was recaptured a week later. She has since been moved to a larger facility to live with a larger group.
• Zoo Choo began operating when the zoo opened in 1952. It originally consisted of a gas-powered Model G-16 miniature train engine, two passenger cars and an observation car. The train operated continuously except between 1994 and 1996 and in 2002. In 2007, it was relocated to the Virginia Museum of Transportation. The zoo replaced it with another G-16 miniature train engine in August 2008.
• Hyde is a female black bear.

The zoo is host to 85 animals among 35 species, including two species on the endangered list, the red panda and snow leopard. It is constantly undergoing changes with a variety of species being added including the opening of an interactive aviary in 2008 and a reptile house in 2009 and the black bear exhibit in 2021. Some of the favorite animals at the Zoo are Bali, the snow leopard; Hyde the black bear, Frank the red panda and Porkchop and Lara the Asian small-clawed otters. Recent additions to the Zoo include various types of poison dart frogs including blue dart frogs and golden dart frogs, = 3 Bennett's Wallabies and a Hoffmann's Two-Toed Sloth, Lady.

• Official website