A sheet feeder includes a loading surface, a supply roller configured to feed recording sheets loaded on the loading surface, an overload prevention member disposed upstream from the supply roller in a sheet feed direction, and a movable member disposed downstream from the overload prevention member in the sheet feed direction. The overload prevention member includes a restriction surface configured to be moved between a first position and a second position. The movable member is configured to be moved from a third position to a fourth position by being pushed by leading ends of the recording sheets. The movable member and the overload prevention member are configured to interlock each other such that, when the movable member is in the third position, the restriction surface is in the first position, and when the movable member is in the fourth position, the restriction surface is in the second position.