ObjectiveThe present study aimed to investigate the effect of long‐acting gonadotropin‐releasing hormone agonist (GnRHa) long protocol on in vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI) outcomes of patients with repeated implantation failure (RIF).MethodsThe present study was carried out from June 1, 2016 to June 30, 2021. A total of 665 patients with RIF were enrolled into the study and classified by the ovarian stimulation protocols. The outcome parameters were compared in each group. In addition, we evaluated the expression of homeobox A10 (HOXA10), integrin β3 and leukemia inhibitory factor (LIF) in endometrial tissues between groups by quantitative RT‐PCR.ResultsPatients who received the long‐acting GnRHa long protocol had significantly higher clinical pregnancy rates (58.0%, 41.7% and 39.9%, respectively; P = 0.008 and 0.003), implantation rates (38.1%, 30.3%, and 30.1%, respectively; P = 0.001 and <0.001) and live birth rates (50.3%, 36.3%, and 31.3%, respectively; P = 0.020 and 0.002) compared with the short‐acting GnRHa long protocol and GnRH antagonist protocol. In addition, we found that long‐acting GnRHa could improve the expression of HOXA10 (P < 0.05).ConclusionThe long‐acting GnRHa long protocol could improve endometrial receptivity and IVF/ICSI clinical outcomes of RIF patients compared with the short‐acting GnRHa long protocol and GnRH antagonist protocol.