Aim The aim of this study was to develop a self-assessment scale for nurses' ethical behaviours for protecting patients' rights and to determine its reliability and validity. Methods This was a methodological study. This study was conducted in public, private and university hospitals in Turkey between August 2018 and May 2019. The sample group consisted of 450 nurses. The item pool was formed with 44 items. After five experts' assessment for content validity, the draft scale was formed with 37 items with a 5-point Likert-type scale. The item-total score correlation and exploratory factor analysis were used. Results The scale included 28 items and five subscales (respect for right to information and decision making, providing fair care, providing benefit-not harming, respect for patient values and choices, attention to privacy). Cronbach's alpha was 0.84 for the whole scale. Conclusion Validity and reliability have been demonstrated for a newly developed scale to measure nurses' ethical behaviours to protect patients' rights.