400 series may refer to:
Consumer graphics cards Radeon RX 400 series GeForce 400 series
Japanese train types 400 Series Shinkansen GV-E400 series, a DEMU train operated by JR East Osaka Metro 400 series, operated by Osaka Metro since 2023
Other 400-series highways, a network of freeways in Southern Ontario, Canada Rover 400 Series, a small British family car GE-400 series, computers produced by General Electric in the 1960s Kodak DCS 400 series, a series of digital SLR cameras produced by Eastman Kodak Toshiba Satellite Pro 400 series, a series of laptops by Toshiba
See also Series 4 (disambiguation) 400 (disambiguation) 4000 series