State Route 78 (SR-78) is a state highway in the U.S. state of Utah that serves as a connector from the town of Levan and SR-28 to I-15 and the Chicken Creek Reservoir in a span of 9.42 miles (15.16 km). The route was formed in 1977 and has preserved its initial state since then.

The road begins at a diamond interchange with I-15 at exit 207. From that point, the route heads northwest as a two-lane undivided highway, running almost parallel to I-15 in the west and Chicken Creek Reservoir in the east. Once the route passes the reservoir, it eventually turns north-northwesterly until reaching the intersection of a local road, where it turns east. The route enters Levan as 100 North and soon terminates at SR-28, the main street of Levan.

State Route 78 was formed in 1977, coinciding with the construction of I-15 through the area, serving the area it does now. The only change that has occurred to the route was a change to the legal definition in 1987, making it more detailed.

The entire route is in Juab County.