Background: Mistreatment of childbearing women continues despite global attention to respectful care. In Ethiopia, although there have been reports of mistreatment of women during maternity care, the influence of this mistreatment on the continuum of maternity care remains unclear. In this paper, we report the prevalence of mistreatment of women from various dimensions, factors related to mistreatment and also its association to the continuum of maternity care in health facilities. Methods: We conducted an institution-based cross-sectional survey among women who gave birth within three months before the data collection period in Western Ethiopia. A total of 760 women participated in a survey conducted face-to-face at five health facilities during child immunization visits. Using a validated survey tool, we assessed mistreatment in four categories and employed a mixed-effects logistic regression model to identify its predictors and its association with the continuum of maternity care, presenting results as adjusted odds ratios (AORs) with their 95% confidence intervals (CIs). Results: Over a third of women (37.4%) experienced interpersonal abuse, 29.9% received substandard care, 50.9% had poor interactions with healthcare providers, and 6.2% faced health system constraints. The odds of mistreatment were higher among women from the lowest economic status, gave birth vaginally and those who encountered complications during pregnancy or birth, while having a companion of choice during maternity care was associated to reduced odds of mistreatment by 42% (AOR = 0.58, 95% CI: [0.42–0.81]). Women who experienced physical abuse, verbal abuse, stigma, or discrimination during maternity care had a significantly reduced likelihood of completing the continuum of care, with their odds decreased by half compared to those who did not face such interpersonal abuse (AOR = 0.49, 95% CI: [0.29–0.83]). Conclusions: Mistreatment of women was found to be a pervasive problem that extends beyond labour and birth, it negatively affects upon maternal continuum of care. Addressing this issue requires an effort to prevent mistreatment through attitude and value transformation trainings. Such interventions should align with a system level actions, including enforcing respectful care as a competency, enhancing health centre functionality, improving the referral system, and influencing communities to demand respectful care.