Motivation is a key ingredient of successful athletic performance over time. Although the concept of maximizing motivation has long been of interest to coaches and practitioners, the vast number of motivational theories, principles, and strategies can seem overwhelming and confusing. Consequently, there is a need for providing more holistic frameworks to coaches and practitioners that not only summarize the essential findings of motivation research but also make the information more understandable and applicable in practical settings. The purpose of this study is to present and test the MUSIC Model of Motivation as a framework that can be applied in performance environments by coaches and practitioners to improve athletes' motivation, engagement, and ultimately, performance. The dissertation includes three related studies. First, I conducted a systematic content analysis to support the application of the MUSIC Model in sports. I analyzed 13 books in the realm of sport psychology and coaching. Results showed strong evidence that the underlying principles and theories of the MUSIC Model are represented in the sports literature, which supports the application of the model as a holistic framework for coaches. For the second study, Brett Jones and I developed a motivation inventory for athletes by modifying an existing motivation inventory for use with athletes. I collected data from student athletes at a large public university and conducted Exploratory Factor Analysis (EFA) with Principal Axis Factoring and Promax Rotation to examine the factor structure of the inventory scales. I used the results of the EFA to make changes to the inventory. Subsequently, I conducted a Confirmatory Factor Analysis (CFA) on a second data set to test for model fit. The fit indices for the CFA demonstrated reasonably good fit to the results, which confirmed the five-factor structure of motivation inventory. Reliability analysis based on Cronbach's alpha showed very good results with alpha ratings ranging between .84 and .94. Overall, the findings provided validity evidence for the produced scores of the MUSIC® Athletic Inventory with student-athletes.