Zoo Knoxville, formerly known as the Knoxville Zoo or Knoxville Zoological Gardens, is a 53-acre (21 ha) zoo located just east of downtown Knoxville, Tennessee, United States, near exit 392 off Interstate 40. The zoo is home to about 1,200 animals and welcomes over 585,000 visitors each year.

Zoo Knoxville is notable for having bred the first two African elephants born in the Western Hemisphere in 1978. The zoo also has bred more endangered red pandas than any other zoo in the world and is a leader in the breeding of endangered tortoises. The zoo is accredited by the Association of Zoos and Aquariums (AZA).

In 1923, a Birthday Fund initiative was started by a local newspaper to start a park for underprivileged children. After slow progress, the Birthday Park was established in 1935 with help from the city of Knoxville and the New Deal. The park included a stone shelter, small playground, and a wading pool on a hillside in Chilhowee Park. Discussion started about introducing a zoo, but funding again became an issue, and the Birthday Park fell into disuse and neglect before being closed in 1946.

In 1948, the Knoxville News Sentinel aimed to revitalize the property as the Birthday Park Zoo using some leftover money from the 1923 initiative, plus more help from the city of Knoxville. In 1951, the zoo was opened and renamed the Municipal Zoo, with the first attraction being an American alligator named "Al". Around 4,000 people visited in the first day of opening.

In 1963, the Ringling Bros. and Barnum & Bailey Circus donated a particularly troublesome seven-ton bull elephant named "Louie", or "Old Diamond". While this initially raised public interest, conditions and funds soon deteriorated, and Old Diamond contributed more problems by tearing up his early enclosures. In 1966, the Metropolitan Planning Commission announced plans to revitalize and modernize the zoo, but a lack of funds once again grounded the project through 1970. Following an effort by the Knoxville Journal to "Save Old Diamond", Dr. Bill Patterson helped found the Appalachian Zoological Society to oversee the formation of an educational zoo. Television executive Guy Lincoln Smith III bought a lion cub and took care of it until money could be raised a proper facility could be built. With these two efforts, the modern Knoxville Zoo was founded in 1971. Smith served as the first director of the zoo until his death in 1987.

In the following years, Old Diamond was successfully mated to two younger female elephants, with two daughters being born in 1978. These were the first two African elephants born in the Western Hemisphere. This set a precedent for Knoxville Zoo to continue to work within the field of conservation until modern times, notably working with red pandas and spider tortoises.

In 2016, Knoxville Zoo announced a massive rebranding campaign alongside a slew of new and revitalized exhibits. With this, zoo executives announced that the property would be renamed Zoo Knoxville, reflecting a change that a few other zoos across the country had done.

Zoo Knoxville is broadly divided two halves, East Zoo and West Zoo. Each section mainly features large and naturalistic outdoor habitats for many of their animal residents, as well as a few smaller indoor exhibits.

Upon entering, the first habitat is Black Bear Falls, housing several American black bears, an important species native to the nearby Great Smoky Mountains National Park. Several viewing areas are featured, as well as a small cave for children to explore educational facts about bears' hibernation behavior and diet.

Continuing to the East Zoo, the Boyd Family Red Panda Village is world-renowned for their red panda conservation program. In 2017, this section of the zoo was greatly expanded and revitalized as the Boyd Family Asian Trek, containing new habitats for Malayan tigers, white-handed gibbons, silvered leaf langurs, and white-naped cranes.

At the east end of the zoo, Clayton Family Kids Cove contains a variety of activities geared towards children. These include a carousel, petting zoo, playground, and sandbox. Regarding animal exhibits, Kids Cove features a petting zoo with a number of domestic animals like sheep and goats, as well as a small exhibit featuring North American beavers and budgies.

The far eastern area of the zoo by Kids Cove formerly held the original reptile house, along with a few smaller exhibits with otters and birds. This, along with other regions along the perimeter of the zoo, are undergoing extensive revitalization as part of the zoo's larger rebranding campaign announced in 2016. As of March 2022, this region of the zoo displays retired birds-of-prey from the zoo's former bird show.

Following the closure of the outdated reptile houses at the eastern end of the zoo, the brand-new Clayton Family Amphibian and Reptile Conservation Campus (ARC) opened just past the Black Bear Falls in the spring of 2021, replacing a smaller "Birds of Central America" exhibit at the center of the zoo. This exhibit containing dozens of indoor naturalistic habitats for various reptile and amphibian species, and it is considered to be massive upgrade from the previous version. Notable species include the Cuban crocodile and various tortoise varieties that are a focal point of the zoo's conservation efforts. The exhibit also features a two-toed sloth.

As part of the second phase of this building complex, the Clayton Otter Creek exhibit features a revitalized habitat for the zoo's North American river otters, opening in March 2022.

A series of smaller buildings populate the pathway between the ARC and Grasslands Africa. One such building is the Pilot Flying J Wee Play Adventure, featuring an indoor playground and assorted activities for children along with smaller herpetology exhibits, the most notable being a Komodo dragon. Just outside of Wee Play is the zoo's Aldabra giant tortoise.

In West Zoo, the largest series of habitats are intended to evoke an African savanna. The Williams Family Giraffe Encounter provides guests with the opportunity to feed reticulated giraffes. Other featured species include Hartmann's mountain zebras, southern white rhinos, southern ground hornbills, and bat-eared foxes. Just past these is a restaurant and a splash pad for children, and farther up is the Valley of the Kings exhibit, housing neighboring exhibits for lions and Hamadryas baboons.

The Stokely African Elephant Preserve formerly housed three African elephants: a male named Tonka and two females named Jana and Edie. As these elephants reached old age, the zoo began an initiative in late 2022 to retire them to The Elephant Sanctuary in Tennessee to receive the proper standard of care for their advanced stage of life. After Edie and Jana were successfully transported to the Sanctuary, Tonka died in May 2024. The existing habitat and barn will be converted to facilitate a breeding program for southern white rhinos.

The rest of West Zoo is largely themed around a bamboo forest leading to Gorilla Valley and Chimp Ridge, housing families of western lowland gorillas and chimpanzees respectively. Other habitats feature species such as African wild dogs, red wolves, yellow-backed duikers, and an elderly Lar gibbon.

The Knoxville Zoo has been successful at breeding several endangered species, especially red pandas and white rhinos. The zoo also bred the first African elephant in captivity in the Western Hemisphere, nicknamed "Lil' Diamond" in 1978.

In 2009, Sarah Glass, curator of red pandas and Special Exhibits at the Knoxville Zoo in Knoxville, Tennessee, was appointed as coordinator for the North American Red Panda Species Survival Plan. The Knoxville Zoo has the largest number of captive red panda births in the Western Hemisphere (101 as of August 2011). Only the Rotterdam Zoo in the Netherlands has had more captive births worldwide.

At the end of 2010, Mozilla Foundation—the creator of Firefox web browser—partnered with Knoxville Zoo in an effort to raise awareness about endangered red pandas. Two red panda cubs born at the Knoxville Zoo have officially become a part of the Mozilla community. The cubs were named Spark and Ember by online voters, and Mozilla broadcast a 24-hour live video stream of the cubs.

The recently opened Amphibian and Reptile Center (ARC) undertakes conservation of endangered species, notably various species of turtles and tortoises.

On January 14, 2011, zookeeper Stephanie James was killed when one of the zoo's two female elephants, "Edie", pushed her into the side of the indoor stall. The incident was deemed to be an accident, not a malicious attack by the elephant. In James' memory, a small fountain and garden is set up between the elephant and rhino exhibits along the Grasslands Africa trek.

• Haskins, Sonya A. Knoxville Zoo. Charleston, South Carolina: Arcadia Publishing. ISBN 9780738544052. OCLC 85860294.

• Official website
• Zoo Knoxville's Conservation Work