ZK may refer to:

Aviation
 Great Lakes Airlines (IATA designator: ZK)
ZK, the aircraft registration prefix for New Zealand

Gaming
 Zero-K, a 2010 real-time strategy game
 ZK, alleged publisher of Sad Satan

Science and technology
 ZK (framework), an AJAX web framework for graphical UIs
 Zero knowledge (disambiguation), various concepts in cryptographic proof
 Zettakelvin, an SI unit of temperature

Other uses
 ZK (rapper), Danish rapper and singer
 Zentralkomitee, the executive body of the Socialist Unity Party of Germany