This study examined adolescent athletes’ expectancy-beliefs, subjective task values, intrinsic motivation, extrinsic motivation and amotivation in sports. Two hundred and five athletes (131 males and 74 females) below 21 years old (15.53 + 2.37) completed the expectancy beliefs, subjective task values measures and the Sports Motivation Scale questionnaire. The two-way ANOVA results indicated a significant interaction effect between age group, and gender, for expectancy beliefs, and age group, for subjective task values in the expectancy-related beliefs and task values measures. Whereas, for the Sports Motivation Scale, the ANOVA results also showed significant interaction effect between age group and gender for intrinsic motivation as well as age group and gender for extrinsic motivation. However, no significant effect was observed between age, gender and locality was found for amotivation. Expectancy-related beliefs were found to be related with subjective task values (r = 0.78) and intrinsic motivation (r = 0.58). Whereas, subjective task values were moderately correlated with intrinsic motivation (r = 0.65) and extrinsic motivation (r = 0.54). Intrinsic motivation was related to extrinsic motivation (r = 0.83) but weakly with amotivation (r = 0.20). The results concluded that adolescent athletes (young generation) showed a trend of higher self-beliefs and values were also more likely to be intrinsically and extrinsically motivated, a combination of both types of motivation as opposed to earlier literature of single motivation type. In addition, our results support the relationship in combining Eccles et al. (1993) Expectancy Theory and Self-Determination Theory to improve understanding of motivation in sports.