Background: Mistreatment of women during childbirth is a global health challenge. Maternity healthcare providers have key roles in influencing women’s birth experiences. This study aimed to assess knowledge, attitudes and practices of maternity healthcare providers about mistreatment during labour and childbirth in public hospitals in Tehran, Iran.Methods: This cross-sectional study was conducted from October to December 2021 in five public hospitals in Tehran. All maternity healthcare providers (obstetricians, midwives) and students were invited to the study. Data were collected using a questionnaire consisting of four sections: socio-demographic characteristics (11 items), knowledge (11 items), attitudes (13 items), and practices (14 items) about mistreatment. Knowledge, attitude, and practice levels were determined using Bloom’s cut off point. Data were analyzed using descriptive and analytical statistics at a significant level of p < 0.05.Results: A total of 255 individuals participated (response rate: 94.5%). Most participants (82.7%) had poor knowledge about physical abuse, verbal abuse, poor rapport between women and providers, and failure to meet professional standards of care. Most participants (69.4%) were alright with physical abuse, verbal abuse, and discrimination. Self-reported practices of different types of mistreatment were not common and only 3.1% of the participants were in moderate level. However, shouted at women, applied fundal pressure, and slapped the thighs during birth were categories used by providers. Age, profession, field of study, employment status, monthly income, work experience, numbers of night shifts, and training history were significantly related with the participants’ knowledge, attitudes, and practices about mistreatment.Conclusions: Knowledge, attitudes, and practices of our participants were poor about maternity mistreatment. Findings of our study have important implications for program planners and decision makers on development of effective interventions to reduce mistreatment during labour and childbirth in Iran. These interventions should include designing and implementing continuing education courses and revising the educational curriculums to increase knowledge, strengthen positive attitudes, and modify practice of maternity healthcare providers, overcoming staff shortages, paying staff fairly, establishing support culture for mother-centered and respectful care, and increasing quality of maternity care.