Three-way connectors are used for pipe fittings and pipeline connections. Also known as three-way pipe fittings, three-way joints, or three-way connectors, they are employed where the main pipeline needs to branch off.

A three-way is a chemical pipeline fitting with three openings: one inlet and two outlets; or two inlets and one outlet. It comes in T-shaped and Y-shaped designs, with both equal and unequal diameter outlets, used at the junctions of three identical or different pipelines. The primary function of a three-way is to alter the fluid direction.