This book is a useful study on locus of control, self-regulation, and vocabulary acquisition. Locus of control as a personality variable has been more important in recent theoretical and applied researches. In acquisition process, learners who have high locus of control are more successful than others. Self-regulation addresses topics such as achievement, learning, and motivation in educational settings and it also provides theoretically and empirically suggestions of ways to apply principles to improve learning and teaching. Furthermore, self-regulation is helpful for learners to find out opportunities for acquisition. This book has shed some light on the problems related to this study. This study might help material developers to provide suitable material for students. Additionally, it might provide valuable help for teachers who seek the significance of locus of control and self-regulation in the vocabulary acquisition through pedagogical intervention in the classrooms.