A protective hood rotation prevention device for a power tool, in particular an angle grinder, includes a clamping unit that is configured to clamp a protective hood unit. The clamping unit includes at least one clamping element with a rotation prevention unit that has a rotation prevention element. The device further includes a movement coupling unit that is configured to move the rotation prevention element in at least one operating state depending on a movement of the clamping element. The device also includes a securing unit that is configured, in at least one operating state, to secure the rotation prevention element, in the event of a movement of the clamping element in a loosening direction of the clamping element, at least as far as possible counter to a movement in an uncoupling direction of the rotation prevention element out of a rotation prevention position of the rotation prevention element.