Matanuska Glacier is a valley glacier in the U.S. state of Alaska. At 27 miles (39 km) long by four miles (6.4 km) wide, it is the largest glacier accessible by car in the United States. Its terminus, the source of the Matanuska River.And lies near the Glenn Highway about 100 miles (160 km) northeast of Anchorage. Matanuska Glacier is "active" and expands around one foot (30 cm) per day. It is open to the public from March to October 31.

An unusual feature of the glacier is the presence of a weather hole, making the weather unusually clear and sunny.

The glacier is the namesake for the Alaska Marine Highway ferry M/V Matanuska.