Physical activity (PA) participation has been linked to broad health benefits including reduced risk of chronic diseases. PA participation is important in adolescence as it sets the precedent for continued engagement and improved long-term health. At baseline, adolescents have some of the lowest rates of physical activity. Subsequently obesity rates in youth have exponentially increased in the past few decades. The existing literature on predictors of youth PA focuses on various internal (e.g., depressive symptoms, anxiety, self-esteem, chronic pain, Body Mass Index) and external (e.g., parental behaviors, risky behaviors) predictors. Some research suggested that internal predictors are more consistent predictors of youth PA, when compared to external predictors. The current study investigated the relationship between both internal and external factors (as well as both facilitators and inhibitors) and PA in youth. Two separate ordinal logistic regression models were utilized. Five internal variables (i.e., depressive symptoms, anxiety, self-esteem, pain, BMI) were significantly related to PA, whereas one of the three external variables were significantly related to PA (i.e., time with friends). Implications include determining important points of intervention to increase PA in youth.