© TÜBİTAK.Goji berry is a lesser-known fruit species and its berries have been used in traditional medicine for centuries as remedies to treat eye, liver, and kidney ailments, as well as for the prevention of cancer symptoms due to its high phytochemical content. This study aimed to investigate changes in the pomological, biochemical, and phytochemical properties of the berries of 4 goji berry genotypes harvested during 4 months (June, July, August, and September) of the same year. The results indicated that the highest berry dimensions (height and width) and soluble solid content were obtained from Genotype 2, harvested in June. The vitamin C, total phenolic, and total anthocyanin contents and 2,2-diphenyl-1-picrylhydrazyl-hydrate values were between 69.06 and 169.96 mg/100 mL, 219.07 and 558.74 mg GAE/L, 2.73 and 107.94 mg/L, and 75.03 and 500.87 µL/mL, respectively, according to the genotypes and harvest months based on a 3-year (2015-2017) average, indicating great variations in both the genotypes and, in particular, the sampling months. Therefore, consumers must take into consideration the harvest times and berries of the genotypes in order to obtain better contents in the berries for human health.