Lightning Lake Dam is a large earthen dam situated at the north end of Lightning Lake in Manning Provincial Park, British Columbia. Built in 1966, it flooded a formerly expansive marshy area to create a significantly larger lake.

The dam also raised the water level enough to establish two separate outlets: water flowing north drains into Little Muddy Creek and eventually reaches the Similkameen River, while the southern outlet feeds into the Lightning Lake chain and ultimately the Skagit River.

The lake sits in a small pass just east of Allison Pass, making it a notable hydrological divide between two distinct watersheds.