South Dakota Highway 377 (SD 377) is a 2.173-mile-long (3.497 km) state highway in Jackson County, South Dakota, United States.

It begins at an intersection with SD 44 in Interior, and travels in a northeasterly direction to its northern terminus at the Interior Entrance Station for Badlands National Park.

It is a near-straight two-lane highway for its entire length.

It ends at the Interior Entrance Station for Badlands National Park.

The entire route is in Jackson County.