A nuclear-powered icebreaker is an icebreaker with an onboard nuclear power plant that produces power for the vessel's propulsion system. Although more expensive to operate, nuclear-powered icebreakers provide a number of advantages over their diesel-powered counterparts, especially along the Northern Sea Route where heavy power demand associated with icebreaking, limited refueling infrastructure along the Siberian coast, and endurance required make diesel-powered icebreaker operations challenging. As of 2023, Russia is the only country that builds and operates nuclear-powered icebreakers, having built a number of such vessels to aid shipping along the Northern Sea Route and Russian arctic outposts since the Soviet era.

An icebreaker is a special-purpose ship or boat designed to move and navigate through ice-covered waters, and provide safe waterways for other boats and ships. Although the term usually refers to ice-breaking ships, it may also refer to smaller vessels, such as the icebreaking boats that were once used on the canals of the United Kingdom.