Consoles :

Atari 2600 (1978)

Atari 5200 (1982)
Emerson Arcadia (1982) : title later changed to "Alien Invaders".

Atari XEGS
Sega SG-1000 (1983)

Nintendo Famicom (1985)

Nintendo Game Boy (1991)

Sega Saturn (1996)

Nintendo Super Famicom (1997, "Space Invaders - The Original Game") : This port is actually "Space Invaders DX" sans the "Parody Game Mode".

Sony PlayStation (1999) : Remake by Activision

Nintendo 64 (1999) : Remake by Activision

Nintendo Game Boy Color (1999) : Remake by Activision

Bandai WonderSwan (1999)
Nuon (2000, "Space Invaders XL")

Nintendo Game Boy Advance (2002) : Remake by Activision

Sony PlayStation 2 (2003, "Space Invaders Anniversary")

Nintendo DS (2005, "Space Invaders DS") : Contains Classic and New Age mode.

Sony PlayStation 2 (2005, "Taito Memories Vol. 1") : Japanese release

Sony PlayStation 2 (2005, "Taito Legends")

Microsoft XBOX (2005, "Taito Legends")

Sony PlayStation 2 (2005, "Taito Memories Vol. 2")

Sony PSP (2005, "Space Invaders - Galaxy Beat") : Japanese release.
Computers :

Exidy Sorcerer (1978, "Invaders")

Microtan 65 (1980, "Space Invasion")
TI99/4a (1981, "TI Invaders" – Texas Instruments)
Tandy Color Computer (1981, "Space Assault")
Tandy Color Computer (1981, "Color Space Invaders")
Vic 20 ("Avenger")
Commodore C64 (1982, "Avenger")
BBC B (1982, "Super Invaders" – Acornsoft)
Sinclair ZX-Spectrum (1982, "Spectral Invaders" – Bug-Byte)
Sinclair ZX-Spectrum (1982, "Space Raiders" – Sinclair Research)
Sinclair ZX-Spectrum (1982, "Invaders" - Artic Computing (UK))
Oric (1983, "Oric Invaders" – Arcadia Software)

MSX (1984)
Tandy Color Computer (1985, "Super Vaders")
Commodore C64 (1987, "Arcade Classics")
Tandy Color Computer 3 (1988, "Space Intruders") : wave 9 is similar to wave 5 of "Phoenix".

Commodore Amiga (1988, "Amoeba Invaders") : included in the cover disk that came with the ST/Amiga Format Magazine (November 1988, Issue number 5).
Atari ST (1989)
X68000 (1989)
Zx-Spectrum (1993, "Invaders" - Design Design Software (UK)) : published exclusively on magazine covertape, appeared on side A of covertape "Your Sinclair issue 85: Christmas Collection 2".
PC [MS-DOS] (1997, "Champ Invaders" - CHAMProgramming)
PC [Windows] (1999) : Remake by Activision

VTech Laser-VZ ("Vz Invaders")

Apple II ("Apple Invader")
PC [MS Windows] (2003, "Space Invaders Anniversary")
PC [MS Windows] (2005, "Taito Legends")
PC9801
Others :
LED handheld game (1980 - Entex (black version))
LED handheld game (1981 - Entex (grey version))
LCD handheld game (1982 - Tiger Electronics)
LCD handheld game with calculator (1982 - Tiger Electronics)
LCD handheld game (larger LCD) (1984 - Tiger Electronics)
VFD handheld game (19?? - Gakken)
LCD handheld game (1999 - Systema)
Arcade Legends : Space Invaders TV Game (2004 - Radica Games)
Mobile Phones (2007, "3D Space Invaders")