We investigate software process diversity, defined as the project condition arising out of the simultaneous use of multiple software development process frameworks within a single project. We analyze the antecedents and consequences of software process diversity and examine the relationship among software process diversity, organizational process compliance, and software project performance. Our conceptualization characterizes software process diversity as the response of a project team to contingencies such as requirements volatility, design and technological novelty, and the level of customer involvement in the project. We empirically tested this conceptualization utilizing a discovery-oriented approach and data collected from 410 large commercial software projects. Results show that higher levels of requirements volatility, design and technological novelty, and customer involvement increased software process diversity within a project. However, software process diversity within a project decreased with an increase in the level of process compliance enforced on the project. We also found that a higher degree of fit (or match) between process diversity and process compliance, rather than those mechanisms independently, was significantly associated with an increase in project productivity and quality. These results indicate that increasing software process diversity in response to project-level contingencies improves project performance only when there is a concomitant increase in organizational process compliance efforts. We discuss the implications of these results for research and derive prescriptive guidelines to manage the fit between process diversity and process compliance for achieving better software project performance.