Abstract: A safety gate assembly is provided for use at a loading dock to prevent accidental or inadvertent movement of a loading dock vehicle through an access passageway provided on the loading dock. The assembly includes a pair of laterally spaced, upright, stationary support members positioned on opposite sides of the passageway and a housing removably mounted on one support member. An elongate gate segment is hingedly connected to the housing for movement between operative passageway-blocking and inoperative passageway-unblocking modes. When in the operative mode, the gate segment spans the distance between the support members. Movement of the gate segment is effected by a motor driven element connected to the segment and disposed within the housing. A stop is mounted for engaging the gate segment only when the latter is in the operative mode.