•Prickly pear fruits are also used for the manufacturing of juices and jams.•The pressed fruit juices of Opuntia ficus–indica are rich in phenolic compounds.•Pulp was the edible part of Opuntia ficus-indica fruit.•Prickly pear seed oil has essential fatty acids. In the study, the impact of harvest time on total phenolic content, antioxidant activity, and phenolic compounds of prickly pear (Opuntia ficus-barbarica A. Berger) fruit pulp and the oil content and fatty acids profile of the seed were investigated. The highest total phenolic content was determined as 156.77 mg/100 g in July 1 harvest, while the maximum antioxidant activity and total oil content were found as 9.81% and 6.80% at the last stage of maturation (15 August), respectively. The highest oleic (28.51%), palmitic (22.61%) and stearic acid contents (9.20%) in seed oil were observed in June 15 harvest. The highest value for linoleic acid (57.50%) was detected in August 15 harvest. Prickly pear is a vital source of bioactive constituents such as phenolic and antioxidant substances in terms of being useful for human health and the optimum harvesting time to retain high quantities of most phenolic compounds is 1st July.