Manju Dinesh Kumara Wanniarachchi (Sinhala: මංජු දිනේෂ් කුමාර වන්නිආරච්චි) (born 2 December 1979) is a Sri Lankan amateur boxer. He won a gold medal at the 2010 Commonwealth Games in the bantamweight category, defeating Sean McGoldrick in the final, but was later stripped of his medal after failing a drug test. He is an old boy of Vidyartha College, Kandy.