$<$h2$>$Abstract$<$/h2$><$h3$>$Background$<$/h3$><$p$>$Studies in high-income countries have found that female physicians exhibit better performance than their male counterparts. However, it is largely unclear whether these findings are influenced by case and patient mix bias. We aimed to objectively assess differences in clinical practice and treatment between female and male primary care providers in rural China.$<$/p$><$h3$>$Methods$<$/h3$><$p$>$In this cross-sectional study, we used standardised patients to assess provider performance in clinical practice, yielding objective performance measures free from case and patient mix bias. We included 309 primary providers who received 412 visits from standardised patients in township health centres in rural areas of three provinces in western, central, and eastern China. All providers were visited by standardised patients who were trained to consistently present three disease cases. Clinical process was graded against checklists based on national and international guidelines of recommended questions and exams to be performed. Assessment of treatment considered the appropriateness of medicine dispensed and referrals made, as well as the types and quantity of medicines dispensed. Unadjusted comparisons of the performance of male and female providers used Ordinary Least Squares (OLS) regressions controlling for disease cases. Adjusted comparisons additionally controlled for facility fixed effects and provider characteristics. We obtained ethics approval from the institutional review boards of Stanford University, USA, and Sichuan University, China. Informed consent was obtained verbally from all providers participating in the study. Consent from village and township providers was obtained as part of the facility survey approximately 5 weeks before visits. All individuals who participated as standardised patients were trained to protect themselves from any invasive tests or procedures.$<$/p$><$h3$>$Findings$<$/h3$><$p$>$In unadjusted comparisons, female providers completed 0$·$76 (95% CI 0$·$05– 1$·$47) more clinical checklist items on average than male providers, representing an increase of 15% over the mean number of checklist items completed by male providers (5$·$04 items). Female providers were also 15 percentage points (95% CI 0– 30) more likely to give appropriate treatment than male providers (38%). Although, there was no significant difference in unadjusted comparisons (43% for female providers and 41% male providers), female providers prescribed significantly fewer unnecessary or harmful medicines such as antibiotics than male providers after controlling for facility fixed effects and other provider characteristics (– 21 percentage points, 95% CI -41 to -2).$<$/p$><$h3$>$Interpretation$<$/h3$><$p$>$This study finds that female providers prescribe fewer unnecessary or harmful treatments in primary care than male providers in rural China after controlling for potential sources of bias. No difference between female and male providers was found for other measures of clinical process quality after adjusting for observable characteristics.$<$/p$><$h3$>$Funding$<$/h3$><$p$>$111 Project (Grant B16031), the Laboratory of Modern Teaching Technology of the Ministry of Education, Shaanxi Normal University, National Natural Science Foundation of China (Grant 71703083), the National Social Science Fund Youth Project (Grant 15CJL005), the National Natural Science Foundation of China (Grant 71703084), and the Knowledge for Change program at The World Bank (Grant 7172469).$<$/p$>$