RSK may stand for:
- Republic of Serbian Krajina
- Robinson–Schensted–Knuth algorithm, between biwords and pairs of tableaux
- Ribosomal s6 kinase, in molecular bio, a signal transducer
- Sanyo Broadcasting, a Japanese radio and TV station
- "Ricky-Steve-Karl," a nickname for the comedy trio of Ricky Gervais, Stephen Merchant and Karl Pilkington.