Mount Erebus /ˈɛrɨbəs/ is the second highest volcano in Antarctica (after Mount Sidley) and the southernmost active volcano on earth. It is the 6th highest ultra mountain on an island. With a summit elevation of 3,794 metres (12,448 ft), it is located on Ross Island, which is also home to three inactive volcanoes, Mount Terror, Mount Bird, and Mount Terra Nova.

The volcano has been observed to be continuously active since 1972 and is the site of the Mount Erebus Volcano Observatory run by the New Mexico Institute of Mining and Technology.