The Curtiss XNBS-4 (or Curtiss Model 36) was a 1920s prototype biplane night bomber built by the Curtiss Aeroplane and Motor Company for the United States Army Air Corps.
The XNBS-4 was developed by Curtiss as an improvement on the Martin NBS-1. Two prototypes, AS68571 and AS68572, were built. The design did not enter production because it offered no significant improvement over the NBS-1.