Izembek Wilderness, Protected wilderness area in Aleutians East Borough, United States.

Izembek Wilderness covers 307,982 acres of the 315,000-acre Izembek National Wildlife Refuge, on the Bering Sea coast of the Aleutians East Borough, Alaska. At its centre lies Izembek Lagoon, 30 miles long and 5 miles wide, holding one of the world's largest eelgrass beds. The refuge is run from offices in Cold Bay.

The United States Congress designated this area as protected wilderness in 1980 under the Alaska National Interest Lands Conservation Act. This law safeguarded the region's fragile ecosystems from development and extraction activities.

Izembek Lagoon was the first wetland in the United States recognized under the Ramsar Convention, in 1986, together with the Izembek State Game Refuge that covers its submerged land. In 2001 the National Audubon Society named the refuge a Globally Important Bird Area. Each fall a quarter-million migratory birds pass through, among them the world's entire black brant population.

Access requires permits and specialized transportation because there are no maintained trails. Temperatures fluctuate between 24°F and 56°F year-round, so proper cold-weather gear is essential.

In 1986 Izembek became the first wetland in the United States listed as a Wetland of International Importance under the Ramsar Convention, and in 2001 the National Audubon Society named it a Globally Important Bird Area. The lagoon's eelgrass beds feed the entire world population of black brant each autumn.