The Seibu 3000 series (西武3000系) was an electric multiple unit (EMU) train type operated by the private railway operator Seibu Railway on commuter services in the Tokyo area of Japan from 1982 until 2014.

[1] Nine 8-car sets (72 vehicles) were built between 1982 and 1987, intended for use on all-stations "Local" services on the Seibu Ikebukuro Line.

[1] The trains were originally painted in the same livery applied to the 101 and 301 series trains, consisting of "lemon yellow" with a "warm grey" band around the windows, and unpainted stainless steel doors, but by 1999, the fleet was repainted in all-over yellow.

[1] By 2014, the fleet consisted of two 8-car sets, based at Kotesashi and Minami-Iriso depots for use on Seibu Ikebukuro Line and Seibu Shinjuku Line workings respectively, and two 6-car sets based at Minami-Iriso.

[3] Ikebukuro Line set 3011 was repainted in a Galaxy Express 999 livery from May 2009, and set 3015 was repainted in a Saitama Seibu Lions baseball team livery from July 2010 and branded "L-train".