This study attempted to investigate the relationship between EFL learners' motivation and internal locus of control under the framework of self-determination theory. In addition, the study examined the relation between EFL learners' age and gender regarding their motivation and internal locus of control. To this end, a convenience sample of 115 university EFL learners both male (n=45) and female (n=70) participated in this study. The instruments applied were two questionnaires: a locus of control questionnaire (Internal Locus of Control Index) and a motivation questionnaire (Laine's Motivation Questionnaire). The results of the Pearson product-moment correlation demonstrated that there was a significant positive relationship between EFL learners' motivation and internal locus of control. Additionally, based on the data analysis, EFL learners' internal locus of control could significantly predict their motivation. Moreover, the findings showed a non-significant correlation between EFL learners' age and their motivation and internal locus of control. Finally, the findings indicated that there was no significant difference between male and female EFL learners regarding their motivation. This study also shows that motivation and internal locus of control facilitate EFL learners' sense of self-determination, autonomy, competence, and relatedness. The findings of the current study can be specifically worthy of attention for EFL teachers by increasing their awareness of the importance of locus of control and motivation and their role in developing English language learning.