The objective this study was to evaluate the effect of different doses of Moringa oleifera leaf extract (MOE) on milk production and milk composition in ewes and on preweaning performance of their lambs. Twenty-four lactating ewes were housed individually with their lambs and assigned to four groups in a completely randomized design. The treatments included a basal diet without MOE (MOE0) or a basal diet supplemented with either 20 mL MOE per ewe per day (MOE20), 40 mL MOE per ewe per day (MOE40) or 60 mL MOE per ewe per day (MOE60). Over 45 days, milk production was recorded weekly and individual milk samples were collected for chemical analysis. Milk yield, fat-corrected milk and daily yields were similar among the four treatments. The supply of MOE did not affect ewe weaning efficiency and average daily gain or litter weaning weight of the lambs. Overall, the results from this study showed that dietary supplementation of hydroalcoholic extracts of Moringa oleifera leaves at doses of 20, 40 or 60 mL/ewes/d in lactating ewes does not have negative effects on milk yield, milk composition or lamb performance.