State Highway 103 in the U.S. state of Colorado runs from I-70 at Idaho Springs to county roads 151 and 103 at Squaw Pass. The thirteen miles (19 km) from Idaho Springs to State Highway 5 forms about half of the Mount Evans Scenic Byway.

The route begins at Idaho Springs, where it heads southwest away from the center of the city and follows the Chicago Creek. After exiting the city, the route begins climbing in elevation, ultimately reaching an elevation of about 10,000 feet, where it meets State Highway 5 at Echo Lake Park. It then passes through Squaw Pass to its terminus at County Route 151.

The route was established in 1923, where it began at U.S. Route 285 and traversed to Idaho Springs. The segment east of Squaw Pass was renumbered in 1954, and the route was entirely paved by 1956.

The entire route is in Clear Creek County.