This investigation was carried out during 2015 and 2016 seasons on twelve trees five years old of "Hollywood" plum trees (Prunus salicina Lindl.) grown in loamy clay soil in a private orchard at Ashmoun, Monofia, governorate, Egypt. Trees were sprayed with (0%, 4%, 5%, 6%) moringa (Moringa oleifera L.) leaf aqueous extract at full bloom stage+fruit setting stage+two weeks after fruit setting stage. Plums treated with 6% moringa leaf aqueous extract exhibited significantly higher setting, yield, fruit weight, firmness, color, Soluble Solid Content (SSC), Titrable Acidity (TA) ratio, ascorbic acid, anthocyanin content, antioxidant activity contents and reducing titrable acidity with reduced fruit drop as compared to all other treatments. It can be concluded that, foliar applications of 6% moringa leaf aqueous extract can be used effectively to improve fruit set, yield, fruit weight, firmness, color, soluble solids content, vitamin C, anthocyanin content and antioxidant activity of "Hollywood" plum.