State Route 178 (SR-178) is a state highway in the U.S. state of Utah. Spanning just 1.2 miles (1.9 km) in Payson, it connects Interstate 15 to SR-198.

State Route 178, a minor arterial connector, starts at Interstate 15's southbound ramp for exit 248, a diamond interchange. The route proceeds east on 800 South, over the interchange, continuing through Payson until terminatining 1.2 miles (1.9 km) at SR-198.

State Route 178 was added to the state highway system in 2000 in exchange for transferring ownership of the western portion of SR-147 from the Utah Department of Transportation to the city of Payson, as SR-178 connected to Interstate 15 and would be a more appropriate road for the state highway system. No changes have been made to the highway since.

The entire route is in Payson, Utah County.

mi	km	Destinations	Notes
0.000	0.000	I-15 south / US 6 west – Las Vegas	Western terminus
0.168	0.270	I-15 north / US 6 east – Salt Lake City
1.198	1.928	SR-198 (State Street)	Eastern terminus
1.000 mi = 1.609 km; 1.000 km = 0.621 mi