RSB
RSB is an abbreviation for:
- Right bundle branch block , a conduction disorder in the heart
- Regional Schnellbahn , a former German type of train
- Revolutionary Socialist League / Fourth International , a communist party
- Rheinischer Schützenbund
- Rigi-Kaltbad-Scheidegg-Bahn , a former railway company in Switzerland
- Return receipt letter , a type of letter delivery in Austria
- Radio Symphony Orchestra Berlin
- Russian State Library
- Railway Shop Battalion , US Army Railroad Operations Battalion
