Recombinant microorganisms, plants, and plant cells are disclosed that have been engineered to express novel recombinant genes encoding steviol biosynthetic enzymes and UDP-glycosyltransferases (UGTs). Such microorganisms, plants, or plant cells can produce steviol or steviol glycosides, e.g., rubusoside or Rebaudioside A, which can be used as natural sweeteners in food products and dietary supplements.