Background and AimsWomen's autonomy in healthcare decision‐making is crucial for improving maternal and child health. Despite its importance, there is limited evidence on autonomous healthcare decision making particularly in postpartum women. Thus, this study aimed to assess the prevalence of postpartum women's autonomy in healthcare decision making and its associated factors in Chencha town, Gamo zone, southern Ethiopia.MethodsA community based cross‐sectional study was conducted among 617 postpartum women in southern Ethiopia from October 1 to November 30, 2023. A study participants were selected by a simple random sampling technique. The data were collected through pretested and interviewer administered questionnaire. Following coding and entry into Epi‐data version 3.1, the data were exported into statistical package for social science software (SPSS version 26) for analysis. A logistic regression model was fitted and, variables with p < 0.05 were declared to be significantly associated with women autonomy in healthcare decision‐making.ResultsIn this study, 61.6% of postpartum women have autonomous in their health care decision making with 95% confidence interval (CI): 57.4, 65.3. Women age over 35 years (AOR = 3.2, 95% CI: 1.7, 6.0), enrollment in community‐based health insurance (AOR = 1.5 95% CI: 1.0, 2.3), having four and above antenatal care visits (AOR = 2.5, 95% CI: 1.6, 3.8), using skilled delivery service (AOR = 4.3, 95% CI: 2.9, 6.6), having primary educational level (AOR = 4.9, 95% CI: 3.0, 8.0), and secondary and above educational level (AOR = 5, 95% CI: 3.1, 8.0) were positively associated with women autonomy in health care decision making.ConclusionThis study revealed that majority of postpartum women were autonomous in their healthcare decision making. Maternal age, educational status, enrollment in community‐based health insurance, having frequent ANC follow‐up and using skilled delivery service were factors significantly associated with women's autonomy. Focus should be given to improve women antenatal care follow‐up and the enrollment of community‐based health insurance.