CDK may refer to:
- The IATA airport code for George T. Lewis Airport, Cedar Key, Florida, United States.
- CDK Systems Ltd, (formerly CDK Electronics) a specialist in refrigeration control and monitoring system.
- CalmDownKidder Records, a netlabel specialising in chiptune music
- Centre for the Study of Democracy and Culture, a Czech think-tank
- Chemistry Development Kit, an open source chemical expert system for Chemoinformatics and Bioinformatics, written in Java
- Chung Do Kwan, founded in 1944, the first of nine schools teaching what came to be known as Taekwondo
- Complete knock down, a production technique, often used in automotive industry
- Curses Development Kit, one of two open source distributions of the Curses widgets library
- Cyclin-dependent kinase, a major class of enzymes involved in the regulation of the cell cycle
- Content Development Kit, packages for allowing content providers to develop applications on a certain platform
- Chronic kidney disease, a progressive loss of renal function of the kidney.