An optical position-measuring device includes a measuring standard as well as a scanning unit movable relative to it along at least one measuring direction, a scanning beam path being formed between the measuring standard and scanning unit and being used to generate displacement-dependent signals. A protective cap is disposed in a manner allowing movement along an axis perpendicular to the measuring-standard plane such that in at least one operating mode, the protective cap for the most part surrounds the scanning beam path between the scanning unit and measuring standard.