In project management, a critical path is the sequence of project network terminal elements with the longest overall duration (project management), determining the shortest time to complete the project.

The duration of the critical path determines the duration of the entire project. Any delay of a terminal element on the critical path directly impacts the planned project completion date (i.e. there is no slack on the critical path).

A project can have several, parallel critical paths. An additional parallel path through the network with the total durations just shorter than the critical path is called a sub-critical path.

Originally, the critical path method considered only logical dependencies among terminal elements. A related concept is the critical chain, which adds resource dependencies.

The critical path method was invented by the DuPont corporation.