The purpose of my dissertation is to examine whether competition among audit partners affects audit quality. While prior research on audit market competition focuses on audit firm-level or office-level analyses, I argue that audit partners, as the primary decision makers in providing audit services, are likely to engage in competitive actions in the audit market. Further, I use spatial distance among audit partners to measure partner-level competition. I conjecture that spatial distance could better reflect the dynamics of audit market competition than the Herfindahl index, the traditional proxy for competition used in most extant studies. Drawing on the spatial economics theory and the social comparison theory, I hypothesize a negative association between competition measured by spatial distance and the quality level delivered by the incumbent audit partner. Using newly available data of U.S. audit partners, this study provides evidence that audit quality is higher (lower) when the spatial distance between the incumbent partner and the closest competing partner is larger (smaller). In addition, the results reveal that the effects of competition measured by spatial distance on audit quality is mainly a partner-level phenomenon rather than an office-level one. Overall, this study highlights the importance of studying competitive dynamics among audit …