State Route 172 (SR-172) is a state highway in the U.S. state of Utah connecting 6200 South and West Valley City to SR-201 and I-80 via 5600 West in a span of . The highway was formed in 1985.
The route begins at the junction of 6200 South and 5600 West and heads due north on the latter as a two-lane undivided highway, with wide shoulders on each side. Past the intersection of SR-173, the road widens to four lanes. Past the diamond interchange at SR-201, the route loses two lanes in each direction. The highway continues in this manner until it terminates at the diamond interchange at I-80.
All of SR-172 has been included in the National Highway System.
State Route 172 was formed in 1985 by the Utah Transportation Commission. Since the route's formation, it has not been changed.