Introduction The aim of this study was to retrospectively determine the objective response rate to hormone therapy (HT) for patients with a measurable adult granulosa cell tumor (GCT) of the ovary in a consecutive series of patients. Material and methods All patients with an adult GCT who were treated with HT steroidal progestins, selective estrogen receptor modulators, aromatase inhibitors and gonadotropin‐releasing hormone agonists within three referral hospitals were identified and their records were screened for HT administration. The main outcome measure was the objective response rate to HT. Results We identified 127 patients with an adult GCT, of whom 81 (64%) had a recurrence. Twenty‐five of these patients (20%) were treated with hormones, of whom 22 had measurable disease at the start of their treatment, i.e. a tumor of more than 1 cm in diameter as seen on imaging, either as a recurrence or as residual disease. The pooled objective response rate, defined as the proportion of patients whose best overall response to hormone therapy was either complete response or partial response to HT, was 18% (4/22) (95% confidence interval 6–41%). In one patient (4.5%) a complete response and in three (14%) a partial response was described. Fourteen patients (64%) had stable disease and in four patients (18%) disease was progressive. Conclusions Although several case reports described good responses to HT in patients with a GCT, we found a response in only four of 22 patients in this relatively large consecutive series of patients.