Background: Adolescence is a critical developmental phase. In sport context, these dynamics are intensified as athletes navigate both performance demands and developmental transitions. Self-Determination Theory (SDT) highlights autonomy, competence, and relatedness as its components and motivational orientations. Although mindfulness interventions are gaining prominence in applied sport psychology, their effectiveness among adolescent athletes remains uncertain. Furthermore, adolescent football players are exposed to mental pressure given the nature of the sport. Examining the predictive role of SDT and motivational factors may guide strategies to facilitate mindfulness outcomes among adolescent football players. Objective: This study aimed to evaluate the predictive role of SDT and motivational factors on the changes in flow and mindfulness following Mindful Sport Performance Enhancement (MSPE), a sport-specific mindfulness intervention among adolescent football players. Method: The study participants included 105 adolescent football players (Mean-age 14.4, 79% males). A pre-post interventional study was employed, obtaining self-reported measures on Physical Education Autonomy, Relatedness, Competence (PE-ARC), Physical Education Motivation (PEMS), Mindfulness (Mindful Attention Awareness Scale -MAAS), and Flow State Scale (FSS-2). The mean difference score was computed for mindfulness and flow as the dependent variable. Linear Regression was performed with PE-ARC, PEMS, and sub-dimensional scores as predictors. Results: Regression analysis indicated that motivation (PEMS) positively predicted improvements in flow state (B= -0.60, p=.013) while self-determination (PE-ARC) negatively predicted improvements (B= -0.49, p= <.001) with 21.4% variance. Amotivation (sub-dimension-PEMS) significantly predicted lower flow, explaining 30.5% variance (B= -3.18, p= .024). Conclusion: Findings indicate that motivational factors predict the effectiveness of mindfulness training on flow outcomes, which is essential for performance enhancement among adolescent football players. Implementation of motivational strategies alongside mindfulness may optimize outcomes. Integration of such tailored programs into coaching, school, and sports authority practices supports adolescent athlete well-being and performance, aligning with SDG 3 (Good Health and Well-being) and SDG-4 (Quality Education)