The beliefs that learners have regarding language learning have been the subject of numerous research studies. But not enough attention has been paid to investigating the nature of learners' beliefs shaped in the process of foreign language learning. Beliefs can affect the learners' language success as well as their learning outcome and behavior. It is important to gain deeper insight about EFL students' perceptions and understand their beliefs since it helps teachers to become familiar with learners' use of learning strategies based on which they can plan a more appropriate language instruction. This study is an attempt to investigate language learning erroneous beliefs and misconceptions of 67 MSc ESP students of midwifery, operating room, and nursing in Isfahan University of Medical Sciences, Iran. They were selected through purposeful sampling and their language learning behaviors were observed by the researcher throughout two consecutive semesters while passing their ESPI and ESPII. Furthermore, data were collected using unstructured field notes and semi-structured interviews. The collected data were analyzed through thematic analysis, the data were coded in line with the research question, and themes as well as sub-themes, were extracted. The findings of this study suggest that action should be taken by the ESP teacher to modify learners'' erroneous beliefs, eliminate negative beliefs, and evolve their simplistic self-instruction beliefs. The findings of the study can inform syllabus design, curriculum development, teacher practice, and material preparation.