GLB may refer to:
- GLB, (standing for gay, lesbian and bisexual), also LGB, an initialism used as a self-designation by what was formerly known as the "gay community". Since the 1990s, LGBT became more used so as to included the transgendered community
- Girls' Life Brigade, a constituent organization of the Girls' Brigade international and interdenominational Christian youth organization
- Goal Line Blitz, a browser-based, American football massive multiplayer online role playing game
- Gramm–Leach–Bliley Act, an act of the 106th United States Congress that repealed part of the Glass–Steagall Act of 1933
- Grant Lee Buffalo, a rock band based in Los Angeles, California
- Infimum (also greatest lower bound), a subset S of some partially ordered set T is the greatest element of T that is less than or equal to all elements of S