Background Incorporating immunotherapy effectively remains a priority in therapeutic research of ovarian cancer, making it essential to conduct and report randomized, controlled trials (RCTs) with high quality. The purpose of this study is to assess the reporting quality of RCTs on immunotherapy for ovarian cancer.Methods This was a cross-sectional, meta-epidemiological study. Two researchers searched Pubmed.gov and embase.com for RCTs published before 25th July 2025 for trials on immunotherapy for ovarian cancer. The 37-point overall quality score (OQS) derived from the 2025 CONSORT statement was adopted to estimate the reporting quality of the contained trials. Linear regression analyses were conducted to explore associations between trial characteristics and overall quality of reporting. Detailed data on blinding, allocation concealment, implementation of the intention-to-treat (ITT) principle, follow-up, endpoint setting and adverse event reporting was collected for a further investigation.Results Totally fifty-three relevant RCTs including 12346 participants (range, 14-1301) were analyzed in this study. The mean OQS was 19.08 (s.d. = 6.07, 95% CI = 17.40, 20.75), reflecting more than 46% of the items were inadequately stated in more than half of the studies. As the key methodological factors, allocation concealment, blinding and intention-to-treat principle were reported in 11 (21%), 22 (42%) and 30 (57%) of the 53 RCTs. Although some trials reported their registration status, none provided details on the registration date; additionally, patient and public involvement (PPI) as well as the inclusion criteria for research centers and intervention implementers were not mentioned in any article. Consequently, all 53 trials scored 0 for these three items, and the next most poorly reported aspect was the handling of missing data, with only 2% (n = 1) of the trials documenting this. Publication after 2010 and completely or partially funded by industry remained independent significant factors of improved OQS in multivariate analysis.Conclusions Randomized controlled trials (RCTs) of immunotherapy for ovarian cancer demonstrate poor reporting of the newly added items in the CONSORT 2025 Statement, while simultaneously exhibiting suboptimal reporting quality of items adhering to previous versions of the Statement—despite the fact that most of the included articles were published after 2010. In order to enhance transparency, minimize resource waste, and avoid misleading clinical decision-making, enhancing reporting of key methodological factors, full trial protocol and adverse events is of primary importance.Trial registration: Not applicable.