Lo Yan Shan, Mountain summit in Chi Ma Wan Peninsula, Hong Kong.

Lo Yan Shan is a granite mountain on the Chi Ma Wan peninsula of southern Lantau Island. Its main peak reaches 303 metres, with a secondary peak of 302 metres to the west-northwest. The Chi Ma Wan Country Trail passes over both peaks, and a fire lookout is stationed on the main summit.

Lo Yan Shan is formed of granitic rock, unlike Lantau Peak and other tall Lantau mountains, which are volcanic. Its two summits, the main peak at 303 metres and a sub-peak at 302 metres to the west-northwest, are both crossed by the Chi Ma Wan Country Trail. The summit fire lookout was set up by the Agriculture, Fisheries and Conservation Department to watch for hill fires in autumn and winter.

The name Lo Yan Shan means "Elderly Mountain", referring to the twin peaks of similar height, 303 m and 302 m. The Chi Ma Wan Country Trail crosses both summits, and the surrounding slopes are granitic rock rather than the volcanic rock of Lantau Peak. Because the area is remote, few people come even on holidays.

The summit is reachable via the Chi Ma Wan Country Trail starting from Pui O village, which connects to multiple access points. The trail is demanding and takes a good amount of time, so allow plenty of hours for the hike.

The fire lookout on the main peak is staffed by the Agriculture, Fisheries and Conservation Department in autumn and winter to watch for hill fires. The mountain has two peaks of nearly equal height: the main peak at 303 metres and a sub-peak to its west-northwest at 302 metres.