A top cover assembly for a monitoring camera assembly that includes a mounting portion arranged for attachment to a mounting base for a monitoring camera, a dome window arranged on the mounting portion and a lining arranged at an inside of the dome window, the lining having a camera view opening adapted to a field of view of the monitoring camera and being rotatable in relation to the mounting portion, and the lining having a guiding portion arranged for engagement with a camera mounting bracket on the mounting base to position the lining in relation to the monitoring camera such that the camera view opening covers the field of view of the monitoring camera, when mounting the top cover assembly on the mounting base, thereby allowing the mounting portion to be rotated in relation to the lining into a position for attaching the mounting portion to the mounting base.