There are three general types of enemies found in Borderlands: creatures, humans, and Guardians, all of whom can come in a Badass (1st Playthrough), BadMutha (2nd Playthrough) version, or SuperBad (After 2nd Playthrough) with the exception of Skags that after 2nd playthrough become "AssKicking".

Several automated weapon systems in Borderlands are also treated as enemies. The Zombie Island of Dr. Ned introduced various creatures of nightmare to the game, loosely collected under the term, "zombie". Claptrap's New Robot Revolution reintroduced the Claptraps as new enemies and added various humans and animals with claptrap robotic upgrades to further swell the Claptrap ranks.

Creatures

• Skag
• Spiderant
• Rakk
• Scythid
• Crab worm larvae
• Trash feeder
• Drifter
• Craw Maggot

Guardians

• Arch Guardian
• Badass Guardian
• Guardian Wraith
• Guardian Spectre
• Principal Guardian
• Sera Guardian

Humans

• Bandit
• Psycho
• Bruiser
• Midget
• Prisoner
• Crimson Lance
• Hyperion Recon Team

Machines

• Lance Probe
• Gatling Turret
• Mulciber Mk2
• Rocket Turret
• Scorpio Turret

Claptraps

• Claptrap Partisan
• Kamikaze Claptrap
• Stabby Claptrap
• Mega Samarai Claptrap

Zombies

• Zombie
• Defiler
• Tankenstein
• Loot Goon
• Torso
• Lance Zombie
• Corpse Eater
• Psycho Zombie
• Skelerakk
• Wereskag
• Suicide Zombie

Bosses

Main article: Boss

Tougher Enemies

Main article: Badass