Objective: Develop and test a tool to measure midwives' perceptions of their role in preceptoring midwifery students. Design: A multi method exploratory study design was used. Population: Preceptor midwives from three maternity units in south-east Queensland Australia. Methods: A three-phase process was used: item generation; expert review; psychometric testing including content analysis of qualitative responses. The survey was online or paper-based and included demographic details, the Clinical Preceptor Experience Evaluation Tool (CPEET) role subscale and draft tool. A focus group discussion explored the open-ended responses. Findings: A large sample of preceptors (n = 164, 64.2 % response rate) participated. Factor analysis revealed a two-factor structure with 24 items accounting for 40.2 % of variance. The mean total score of the Midwifery Perceptions and Assessment of Clinical Teaching (MidPaACT) tool was 103.31 (SD = 9.47). The scale was reliable (Cronbach's alpha 0.89) and valid. Test-retest reliability showed moderate to excellent temporal stability across the scale and subscales. Measures of concurrent validity showed little agreement with the CPEET tool. Qualitative analysis revealed the way midwives were taught as students had a powerful influence on their approach to teaching in practice. Conclusion: This tool is specifically designed to assess midwifery preceptors' perceptions of their role in student learning in practice. Psychometric testing of the MidPaACT tool confirms its reliability and validity. Implications for practice: Midwifery preceptors are a key influence on the development of students' capability as a midwife. Midwives' perceptions of their proficiency in student learning are under-reported. The MidPaACT tool provides a reliable and valid means of measuring preceptors' perceptions and identifying areas for future educational and workforce improvement.