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

A three-way fitting is a type of pipeline fitting with 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 openings, and is used at the junctions where three identical or different pipelines converge. The primary function of a three-way fitting is to alter the direction of the fluid flow.