Various examples of a tool-free dust cover for firearms are described. The dust cover is a monolithic piece having a cover plate, a first connection portion, and a second connection portion, with at least one of the first connection portion and the second connection portion being elastically deformable to allow the dust cover to be pivotably coupled to a receiver portion of the firearm. The first connection portion is received in a cavity of a first hinge knuckle on the receiver portion next to a first long side of an ejection port of the receiver portion. The second connection portion is received in a cavity of a second hinge knuckle on the receiver portion next to the first long side of the ejection port. When in an open position, the cover plate uncovers the ejection port. When in a closed position, the cover plate covers the ejection port.