Among the factors influencing learners' learning, autonomy, self- efficacy, and critical- thinking are thought to be of crucial importance. The purpose of the present study was to investigate the relationship among Autonomy, self-efficacy, and critical thinking of Iranian upper-intermediate EFL learners. To this end, a sample of 89 male and female EFL students, aging from 18 to 40, at the upper intermediate level from 4 different classes were chosen based on convenience sampling. After administering the Oxford Placement Test (OPT) to 89 participants, 60 of them were considered homogenous members based on their scores ranging from 37 to 47, which according to the guide of the OPT, fall within the upper-intermediate level. The students were asked to fill out the learner autonomy, critical thinking, and self-efficacy questionnaires. The result of the study indicated that there was positive and significant relationship between Iranian EFL students’ autonomy and self-efficacy (rs = .62, p<.05), self-efficacy and critical thinking (rs = .88, p<.05), and critical thinking and autonomy (rs = .62, p<.05). It was concluded that by being aware of autonomy, self-efficacy, and critical thinking and their positive association, teachers can more beneficially help students in the process of language learning.