The following highways are numbered 378:
Canada Saskatchewan Highway 378
Japan Japan National Route 378
United States Interstate 378 (former) U.S. Route 378 Georgia State Route 378 Louisiana Highway 378 Maryland Route 378 (unsigned) Nevada State Route 378 (former) New Mexico State Road 378 New York State Route 378 Ohio State Route 378 Pennsylvania Route 378 Puerto Rico Highway 378 Virginia State Route 378