RK may refer to:
Science and technology Radial keratotomy, a surgical procedure on the eye Rhodopsin kinase, an enzyme r/K selection theory, in biology, relating to the trade-off between quantity and quality of offspring Runge–Kutta methods, in numerical analysis
Airlines Royal Khmer Airlines (former IATA code: RK), ceased operations 2007 R Airlines (former IATA code: RK), ceased operations 2018 Ryanair UK (IATA code: RK), UK based subsidiary airline of Ryanair
Other uses Radha Krishnan Chidambaram, Indian actor and producer, known as RK Raising Kaine, a defunct political blog in Virginia, US Reichskommissariat, a historical Nazi territorial division in Europe Rangkasbitung railway station, station code RK, Indonesia Ridwan Kamil, former governor of West Java province, Indonesia
See also RK (), Finnish assault rifles; for example RK 62 Republic of Korea (ROK) Republic of Kazakhstan