Abstract Study objective To investigate the impact of an ovarian dermoid cyst or dermoid cyst surgery on ovarian reserve in patients undergoing in vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI). Design We performed a retrospective cohort study by using the records of patients with a history of ovarian dermoid cyst who underwent IVF/ICSI between 2009 and 2013. The antral follicle count (AFC) obtained by transvaginal ultrasound during controlled ovarian hyperstimulation of IVF/ICSI, total number of basal follicles [i.e., basal antral follicle count (B-AFC)], and dominant follicles greater than 1.4 cm [i.e., dominant antral follicle count (D-AFC)] were calculated between the different groups. Patients We included 260 patients with a history of dermoid cyst excision and 23 patients with a dermoid cyst who underwent IVF/ICSI. Two hundred and eighty-three matched patients without a dermoid cyst and ovarian surgery history were included. Intervention None. Measurements and main results The B-AFC was significantly smaller in the dermoid cyst group than in the matched control group ( p = 0.030). The B-AFC and D-AFC were both significantly smaller for the previously operated ovary than for the contralateral nonoperated ovary ( p = p = 0.018 and p = 0.004, respectively). The B-AFC and D-AFC were significantly fewer in ovaries treated by open surgery than in ovaries treated laparoscopically ( p = 0.031 and p = 0.028, respectively). There was no significant difference in the main IVF outcomes between the two groups or the subgroups. Conclusion Our results suggest that ovarian dermoid cyst excision could significantly reduce ovarian reserve to a similar extent as the cyst itself. The presence or resection of dermoid cysts will not affect the main IVF outcomes.