For other uses, see Legion of Doom (disambiguation).

The Legion of Doom (LOD) was an influential hacker group from the 1980s and 1990s. It released the LOD Technical Journals .

The Legion of Doom was founded by the hacker Lex Luthor to educate new generations of hackers on the internet. The Legion of Doom split into two factions after Phiber Optik (a new member of LOD) was thrown out because of a feud with Erik Bloodaxe. Phiber Optik joined another group, the Masters of Deception as did some other former LOD members who opposed Erik Bloodaxe. The division of these two rival hacker factions led to the Great Hacker War, where both groups competed for prestige in the hacker community by gaining access to computer and telephone networks.

The Legion of Doom disbanded in the early 90's after Operation Sundevil and Operation Redux began the era of US Secret Service crackdowns on hacker groups.