DKB may stand for:
- Dai-Ichi Kangyo Bank, a Japanese bank, one of the predecessors of Mizuho Financial Group
- Danish Royal Library (Det Kongelige Bibliotek), the national library of Denmark
- Deutsche Kreditbank, a German direct bank owned by BayernLB
- Diethelm Keller Brands, Swiss business
- Donny Kelly Baby, a nickname for MLB player Don Kelly (baseball).