The aim of this study was to draw a map to understand auditors' self-development behavior and analyze its impact on audit quality. In this direction, relying on methodological argumentative foundations, two qualitative and quantitative approaches were used in parallel to comprehensively examine the different dimensions of this phenomenon. In the qualitative part, by using the content analysis method and conducting in-depth interviews with experts, the components of auditors' self-development behavior were extracted. A standard questionnaire was also used to measure auditors' professional judgment in order to measure the dimensions of this construct more accurately. Finally, structural equation modeling with the partial least squares method (PLS-SEM) was used to test the research hypotheses. The results of the present study indicated 3 overarching themes (professional self-awareness, continuous learning, and responsibility and commitment to the profession), 6 organizing themes (deep understanding of the role of auditors, development of auditors' critical insight, updating of auditors' technical knowledge, development of auditors' soft skills, commitment to auditors' professional ethics, and auditors' accountability to society), and 58 basic themes. Also, the findings from the quantitative part showed that auditors' self-development behavior has a positive and significant effect on audit quality. The findings of this study can have many achievements and applications for regulators, policymakers of the auditing profession, and other regulatory institutions in the Iranian audit market, and help them to adopt mechanisms and laws to improve professional judgment and audit quality by better understanding the themes of auditors' self-development behavior.