William Sargent Ladd was an American politician and businessman in Oregon. He twice served as Portland, Oregon's mayor in the 1850s. A native of Vermont, he was a prominent figure in the early development of Portland, and co-founded the first bank in the state in 1859. Ladd also built the first brick building in Portland and was a noted philanthropist. Part of his former estate, the Ladd Carriage House, is on the National Register of Historic Places.

The Ladd Carriage House is a building in downtown Portland, Oregon, at Broadway and Columbia. It is one of the few surviving buildings forming part of the former grand estates which once stood in the downtown core. It is listed on the National Register of Historic Places.