Xestia smithii, or Smith's dart, is a moth of the family Noctuidae. The species was first described by Pieter Cornelius Tobias Snellen in 1896. It is found across northern North America from Newfoundland to Alaska. In the eastern United States it occurs from Maine to Virginia and south along the Appalachians to North Carolina. In the west it is found in the Black Hills in western South Dakota and north-eastern Wyoming, in the Rocky Mountains from Montana to New Mexico, south-eastern Arizona, and from Washington to east central California. It has recently been recorded from Tennessee.