The Great Lakes Waterway is a system of channels and canals that makes all of the Great Lakes accessible to oceangoing vessels. Its principal civil engineering components are the Welland Canal, bypassing Niagara Falls between Lake Ontario and Lake Erie, and the Sault locks, bypassing the rapids of the St. Marys River between Lake Superior and Lake Huron, at Sault Sainte Marie. Maintained channels serve the St. Clair River and Detroit River between Lake Huron and Lake Erie.

The Great Lakes Waterway is supplemented by the Saint Lawrence Seaway, which makes the Saint Lawrence River navigable from Montreal to Kingston, Ontario. The two waterways are often jointly referred to as the St. Lawrence Seaway.

The Great Lakes Waterway is co-administered by Canada and the United States.