Given the demands of revised student learning standards, today's teachers face mounting pressure for their students to produce content knowledge and skills ensuring a successful transition to college and careers. An emphasis on teacher learning and professional development has been at the forefront of this transition to best prepare teachers to meet these learning goals. We sought to understand how a self-directed model of teacher professional learning, GO-Time, influenced teachers' motivation to engage in professional learning and produce learning outcomes. We used Self-Determination Theory as a frame to understand teachers' experience of motivation in this self-directed learning program. Twenty-seven teachers from a suburban district in the northeast US completed an online questionnaire including Likert-type scales (i.e., independent variables: needs satisfaction, perceived autonomy support, perceived work engagement, teaching self-efficacy (TSE); dependent variable vitality) and open-ended questions. Descriptive statistics and correlation analyses for RQ1 revealed moderate, statistically significant relationships between vitality and engagement (r=0.45, p<0.05) and between vitality and TSE (r=0.38, p<0.05). These findings suggest that higher levels of engagement and TSE are associated with higher levels of teachers' sense of vitality. For RQ2, multiple regression results indicated that engagement emerged as a significant predictor of teachers' sense of vitality ([beta]=0.48; p<0.05), while autonomy support, needs satisfaction, and TSE were not significant predictors. This highlights the critical role of teachers' active involvement and enthusiasm in enhancing their sense of vitality. Qualitative analyses revealed that teachers in this professional development model reported a sense of perceived professionalism, a direct connection or relevance to their practice, and an environment conducive to their engagement. Significance and implications for practice are discussed.