Objective: Isotretinoin is used in acne vulgaris treatment for more than 20 years. Isotretinoin has serious side effects on many organs, but there are no comprehensive studies investigating its possible toxic effects on reproductive organs. Thus, we aimed to investigate the possible toxic effects of isotretinoin administration on oocyte maturation in female rat gonads in this study. Methods: Thirty-two adolescent female rats (Wistar Albino, 220 ± 35 g) were randomly divided into 4 groups with 8 subjects in each group: group 1, group 2, group 3, and group 4. Different doses of isotretinoin which was dissolved in sesame oil were given to rats by gavage: 7.5 mg/kg/day in group 3 and 15 mg/kg/day in group 4. The rats in group 2 received sesame oil by gavage. To create gavage stress, only gavage was administered to the rats in group 1. The gavages for each group continued once a day and at a certain time for 30 days. To determine the effect of isotretinoin on oocyte maturation, the periodic acid-Schiff reaction was performed for histochemical and histomorphometric evaluation of the zona pellucida, and staining of growth differentiation factor-9 (GDF-9) and bone morphogenetic protein-15 (BMP-15) was performed for immunohistochemical analysis. Results: When the thickness of the zona pellucida was evaluated, a statistically significant difference was found between group 1 and experimental groups (group 3 and group 4). In the experimental groups, it was determined that the thickness of the zona pellucida was decreased depending on the increase in dose. GDF-9 and BMP-15 expressions in oocytes of primordial and primary follicles decreased significantly in the experimental groups compared to group 1 and group 2. However, the expression of GDF-9 and BMP-15 in oocytes of secondary follicles was not significantly different between group 1 and group 2 and the experimental groups. Conclusions: In our study, we showed toxic effect of isotretinoin on oocyte maturation in female rats.