Defender inspired numerous similar games, including Orbiter, Attack of the Mutant Camels, Repton and Dropzone for 8-bit home computers; Datastorm, Overkill, Star Ray and Guardian for the Amiga, as well as Provocator on the Acorn Archimedes; Eliminator for the TRS-80; and Protector II for the TRS-80 Color Computer and Atari 400/800, Planet Raiders for the TRS-80 Color Computer. It was also the inspiration for Chopper Command for the Atari 2600.
In 1982, Williams Electronics, the pinball division, released a pinball table based upon Defender.
In 1982, Buckner and Garcia recorded a song titled "The Defender", using sound effects from the game, and released it on the album Pac-Man Fever.
The Beastie Boys have also rapped about the game and featured Defender sound effects in their tracks. In their song Body Movin' (from Hello Nasty, 1998) the lyrics are "And if you play Defender I could be your hyper space", referring to helping the active player by being ready to press the difficult-to-reach hyperspace button when the game gets too difficult.