An efficient procedure for the preparation of homochiral (R)-(+)-γ-decalactone 4 based on castor oil ozonolysis is described. The key intermediate, (R)-(−)-1,3-nonandiol 1, was transformed into monotosylate 2 and then reacted with sodium cyanide to give 3. Treatment of the latter with a dilute hydrochloric acid provided the enantiomerically pure lactone 4.