It is important to determine the most suitable ripening period of fruit regarding bioactive compounds for evaluating as an industrial and in human nutrition. The aims of this study were to determine the changes in non-anthocyanin phenolics, anthocyanins, and antioxidant activity of Mahonia aquifolium fruit throughout ripening and to determine the biosynthetic pathway of the phenolic compounds. The fruit was collected from shrubs at 10 different ripening stages between June 21 and August 17, 2016. The samples were analyzed for individual anthocyanins, non-anthocyanin phenolics, and antioxidant activity. There were significant decreases in gentisic, chlorogenic, p-coumaric, ferulic acids, rutin, and isorhamnetin 3-O-glucoside and increases in protocatechuic, syringic acid, caffeic acid, myricetin, and luteolin. The concentrations of delphinidin-3-O-glucoside, cyanidin-3-O-glucoside, and pelargonidin-3-O-glucoside rose progressively from the beginning to the end of ripening, while decreases occurred from the 6th stage in the amounts of malvidin-3-O-glucoside, peonidin-3-O-glucoside, cyanidin-3-O-rutinoside, and delphinidin-3-O-rutinoside. A decrease followed by an increase in the antioxidant activity indicated that the phenolic profile of the fruit changed toward the end of ripening, including for the compounds with higher antioxidant potential. In this study, the most suitable harvesting period for Mahonia berries was determined