O'Neill Butte is a 6,071-foot (1,850 m)-elevation summit located in the Grand Canyon, in Coconino County of northern Arizona, United States.

Topographic relief is significant as O'Neill Butte rises 3,600 feet (1,100 m) above the Colorado River in two miles (3.2 km).

[4] The summit block of O'Neill Butte is composed of Permian Esplanade Sandstone, which is the uppermost member of the Pennsylvanian-Permian Supai Group.

[6] The cliff-forming Redwall overlays the Cambrian Tonto Group, and below that Paleoproterozoic Vishnu Basement Rocks at river level in Granite Gorge.

This feature is named for William Owen "Buckey" O'Neill (1860–1898), an Arizona Territory politician, who died as a captain of Theodore Roosevelt's Rough Riders at the Battle of San Juan Hill.