U.S. Route 77 (US 77) is a major north–south United States Numbered Highway which extends for 1,305 miles (2,100 km) in the central United States. As of 2005, Its southern terminus is in Brownsville, Texas, at Veteran's International Bridge on the Mexican border, where it connects with both Mexican Federal Highway 101 and Mexican Federal Highway 180, and the highway's northern terminus is in Sioux City, Iowa, at an interchange with Interstate 29 (I-29), less than 1⁄2 mile (800 m) north of the Nebraska state line.

It is unsigned in and around Dallas, Texas. Its historic segment through South Dakota and Minnesota was decommissioned with the advent of I-29 but otherwise the route has been spared the decommissioning that has shortened other US Highways. The route has major freeway sections in Oklahoma City including the Broadway Extension connecting suburban Edmond to downtown Oklahoma City.

The section between the Oklahoma–Texas state line and Waco is mostly co-located with I-35 and the I-35E branch through Dallas, and where it is co-located, it is not signed.

The two stretches in Texas that are not co-located are a stretch wholly within the city of Denton and a longer stretch from near Red Oak, to Hillsboro, the reason being that US 77 is a separate road between the two, serving the town of Waxahachie.

As of 2004, US 77 Alternate has a northern terminus in Hallettsville, Texas. It rejoins US 77 at Refugio, Texas. While the main line of US 77 passes through Victoria, Alternate US 77 veers to the west to serve Yoakum and Cuero.

The southern end extends from I-37 near Corpus Christi to Harlingen, where it merges with US 83 and runs through the cities of Harlingen, San Benito and Brownsville to its southern terminus at the United States/Mexico border.

A section of US 77 located in the Giddings, Texas area is known as the Martin Luther King Jr. Memorial Highway.

Another section of US 77, from I-37 to SH 44 in Nueces County, was redesignated I-69/US 77 in 2011.