Aoshima (Japanese: 青島, Hepburn: Aoshima), also known as Cat Island (Japanese: 猫の島, Hepburn: Neko no shima), is an island in Ehime Prefecture, Japan, known for its large number of feline residents and small number of people.

Felines have been reported by news outlets to outnumber humans by ratios between 6:1 and 10:1, but as elderly inhabitants of the island have died, the ratio has greatly increased, to almost 36:1. Cats were introduced to combat rodents on fishing boats but remained on the island and reproduced in large numbers.

The feline inhabitants of Aoshima are fed by food donations from all over Japan. They also eat small animals on the island and food from visitors.

The island is roughly 1.6 kilometres (1 mi) long. It was formerly part of Nagahama in Kita District, but as of 2005, it is part of Ōzu city.

The human population on the island has decreased since sardine fisheries became depleted and jobs moved to cities. As of December 2024, only four people are still living on Aoshima, while the number of cats has dropped to 80.

Originally, Aoshima was an uninhabited island. The village was formed in 1639 by the collective relocation of 16 families and their descendants from Sakoshi Village in Banshu (now Sakoshi, Akō city), and developed as a sardine fishing village with a secondary farming industry.

Aoshima was a fishing village supported by the sardine trade; the fishermen would bring cats with them to control the rodent problem, eventually leaving cats on the island as they departed. That's when the cat population began growing. Eventually the cat population grew thanks to the support of locals. However, with years the sardine trade has dwindled and the majority of people abandoned the island to seek better life on the mainland.

The Aoshima Elementary School was closed in March 1979 and has since been used as a community center, and is currently used as a temporary accommodation facility for visitors to the island.

As of 2024, the number of off-limit areas in Aoshima is increasing. The road leading to the breakwater has been closed off. Entry to areas inhabited by islanders is prohibited. Due to weather conditions (typhoons, heavy rains, strong winds), abandoned houses have collapsed and blocked some roads. There is a possibility that the island will become uninhabited in five years.