BDK may refer to:
- Base Derivation Key, the key used jointly by the PIN Pads and your jPOS implementation to create and transport DUKPT-enabled PIN blocks.
- Bruderschaft des Kreuzes, a professional wrestling stable in Chikara
- Bundu dia Kongo, a politico-religious group in Bas Kongo, Democratic Republic of the Congo
- Big Daddy Kane, an American rapper.
- Quebec comics, called by some in the 1970s Bande dessinée kébécoise