BACKGROUND-AIM Human being is exposed to bisphenol A (BPA), a plasticizer used in food containers, through diet. Granulosa cell (GC) play a fundamental role for oocyte growth and maturation. BPA impaired GC steroidogenesis and has been classified as an endocrine disruptor (ED). BPA was banned from the food industry and replaced by structural analogues, particularly bisphenol S (BPS). Given that the ewe has similar follicle kinetic compared to women, the evaluation of the effects of BPS on the ovine would allow to investigate whether the ewe is a suitable model to study ED effects in human. Our objective was therefore to assess BPS effects, and its mechanisms of action, on both human and ovine GC. METHODS After puncture of follicles from women undergoing in vitro fertilization or ewe ovaries (slaughterhouses), GC were collected, purified and treated in complemented serumfree Mc Coy Medium, with BPS (1 μM, 10 μM or 50 μM) for 48-h. We analysed GC viability (adenylate kinase activity assay) and proliferation (incorporation of BrDU), secretion of oestradiol and progesterone (ELISA essay), expression of steroidogenic enzymes (Western Blot), hormonal receptor gene expression (quantitative RT-PCR) and MAPK3/1 signalling pathway, as it is involved in both survival and proliferation cellular process (Western Blot). Results were analysed using non parametric permutational ANOVA and Tuckey post-hoc test. RESULTS BPS 10 μM significantly decreased progesterone secretion of both human (16 %; p = 0.0059) and ovine (22 %; p = 0.0402) GC compared to control. BPS 50 μM significantly decreased oestradiol secretion in human GC (46%; p < 0.0001), while it was significantly increased with BPS 10 μM in ovine GC (198%; p = 0.0082). In both ovine and human GC, BPS did not affect cell viability, proliferation, protein expression of steroidogenic enzymes, PR gene expression, or MAPK3/1 phosphorylation. CONCLUSIONS Thus, the effects of BPS on GC appear harmful and similar between human and ovine; except for oestradiol secretion, likely due to the ovulatory stage of GC collection for women. Our data confirmed that the ewe is a relevant model, in term of sensitivity, for the human female reproduction. Ewe GC will allow us to further study the detailed mechanisms of action of BPS on female reproduction.