The olive leaf moth Palpita unionalis (Lepidoptera: Pyralidae) is an economic pest of the olive groves in Egypt and other olive producing countries in the world. The present study was conducted aiming to assess the effects of Methoxyfenozide, on adult performance and reproductive potential after treatment of newly moulted last (6th) instar larvae with sublethal concentrations (0.001, 0.01, 0.10, 1.00 and 10.0 ppm) of the tested ecdysteroid agonist.Methoxyfenozide could not affect the adult morphogenesis but displayed adulticidal effects (10% mortality) only at 0.10 and 1.00 ppm and arrested the adult emergence, especially at the higher four concentrations. The total adult longevity, pre-oviposition period andpost-oviposition period had been pronouncedly prolonged, in a dose-dependent course, but the oviposition period was slightly shortened. Oviposition efficiency of the successfully emerged females was pronouncedly inhibited, in a dose-dependent trend. Fecundity and fertility were tremendously reduced, in a dose-dependent course. The embryonic development was drastically retarded, since the incubation period was significantly prolonged, proportional to the concentration.