Introduction: Teachers' knowledge of self-directed learning and critical thinking are two predictors of learning in learners. This knowledge has impact on promotion of active learning process and academic achievement. This study evaluates the relation between tendency to critical thinking and self-direction in nursing and midwifery students and its role on their academic achievement. Methods: All undergraduate students of nursing and midwifery school Mashhad University of Medical Sciences (N=550) were studies. Thirty nine percents (n=214) of students responded (%26 males and %74 females). Method of study was descriptive. Results: There was no significant relationship between self-direction and tendency to critical thinking and Academic Achievement (P >0.05). However, there was significant and positive relationship between self-direction and tendency to critical thinking (P < 0.0001, r: 0.45).there was no significant difference between male and female students in self- directed and tendency to critical thinking scales (P> 0.05). However there was significant difference between academic achievement of male and female students (P< 0.001). Conclusion: Results show that there is no significant relationship between self-direction and tendency to critical thinking and academic achievement. However, there was significant and positive relationship between self-direction and tendency to critical thinking.