The Keio 3000 series (京王3000系, Keiō 3000-kei) was a DC electric multiple unit (EMU) train type operated by Keio Corporation on the Keio Inokashira Line in Japan from 1962 until 2011.
 The 3000 series was the first Keio rolling stock to use completely stainless steel body construction. A total of 29 5-car sets (145 cars) were built from 1962 by Tokyu Car, and in 1963, the design was the recipient of the third Laurel Prize presented annually by the Japan Railfan Club.
 Each trainset featured a livery in one of the seven pastel hues corresponding to a train configuration, a unique feature found only on the Inokashira line. A number of trains were later resold to operate on other lines throughout Japan.
 The five-car trains were formed of three motored ("M") intermediate cars and two non-powered driving trailer ("Tc") cars as shown below with car 1 at the Kichijoji (western) end.
 The first trains entered service on the Inokashira Line in 1962. The fleet underwent refurbishment from 1996, with the original fibre-reinforced plastic (FRP) cab ends replaced by new steel cab ends with panoramic windscreens and front skirts.
 Withdrawal of the 3000 series fleet began in 1996 following the introduction of new 1000 series sets. The last remaining sets were withdrawn by the end of 2011. The withdrawal dates for the later, refurbished sets were as shown below.
 A number of sets were resold to other private railway companies, including the Hokuriku Railroad, Jomo Electric Railway, Gakunan Railway, Matsumoto Electric Railway (Alpico Kotsu), and Iyo Railway. In 2007, it was announced that former 3000 series EMUs would be resold to the Choshi Electric Railway in Choshi, Chiba, and converted to two-car sets. However, this plan was cancelled due to the cost of converting the 1,500 V DC cars to 600 V DC operation.
 Two early, narrow-body 3000 series sets were resold to the Hokuriku Railroad in Kanazawa, Ishikawa, where they became two-car 8800 series sets 8801 to 8802. Later, wide-body sets were also resold to become two-car 7700 series set 7701 and 8900 series sets 8901 to 8903.
 Eight 3000 series sets were resold to the Jomo Electric Railway in Gunma Prefecture, where they became two car 700 series sets 711 to 718.
 Five former 3000 series cars were resold to the Gakunan Railway in Fuji, Shizuoka, where they became two-car 8000 series set 8001 and three single-car 7000 series units, 7001 to 7003.
 Four former 3000 series sets were resold to the Matsumoto Electric Railway (present-day Alpico Kotsu) in Nagano Prefecture, where they became two-car 3000 series sets 3001 to 3007.
 Ten sets, 3720 to 3729, were resold to the Iyo Railway (Iyotetsu) in Matsuyama, Ehime, where they became three-car 3000 series sets 3301 to 3310.
 Car 3719 is preserved at the Keio Rail-Land open-air museum next to Tama-Dōbutsukōen Station on the Keio Dōbutsuen Line in Hino, Tokyo, which opened in October 2013. Car 3719 was built in 1979 by Tokyo Car, and was withdrawn in March 2009.
 Inherited from Keio Electric Tramway / Gyokunan Electric Railway : DeHa 2000 series (I) · DeHa→SaHa 2110 series · DeHa 2125 series · DeHa 2150 series · DeHa 2200 series · DeHa 2300 series · DeHa 2400 series · DeHa 2500 series (DeHa 2500 and DeHa 2501~2504) · 220 series
 Inherited from Teito Electric Railway : DeHa 1400 and KuHa→SaHa 1200 series · KuHa 1500 series