The Seibu 10000 series (西武10000系) is an electric multiple unit (EMU) train type operated by the private railway operator Seibu Railway on limited express services in the Tokyo area of Japan since 1993.

Seibu Railway Company, Ltd. is a conglomerate based in Tokorozawa, Saitama, Japan, with principal business areas in railways, tourism, and real estate. Seibu Railway's operations are concentrated in northwest Tokyo and Saitama Prefecture; the name "Seibu" is an abbreviation of "west Musashi", referring to the historic name for this area. It and its holding company hold shares of numerous bus, hotel and tourism operations nationwide.