This research aimed to investigate students difficulties in writing thesis and the most difficult factor between internal and external factor in writing thesis of English Education Study Program Students of IKIP PGRI Pontianak in the academic year 2020/2021. The researcher used descriptive study as researh design of this research. The research conducted by spreading questionnaire and doing interview. There were 12 students selected by purposive sampling as respondents for this research. The questionnaire used to answer questions for the most difficult factor between internal or external in writing thesis. Whereas, interview was a tool of data collection used to find factor difficulties in writing thesis. From questionnaire data, it showed that 67% students had difficulties in internal factor. Then, 54% students had difficulties in external factor. From the result, it could be said that the most difficult factor in writing thesis was personality factor or internal factor. From interview, it found that factor difficulties confronted by students in writing thesis was choosing topic or problem to be researched. Students also stated that having difficulties in choosing proper literature review. In sociocultural factors, students mentioned that standard format of writing thesis in the university was hard to understand and they still need guidance from their supervisor in order to write with the correct standard format. In linguistic factor, the respondents explained that their were experienced difficulties to paraphrase sentences from the sources to the thesis writing. Because they were lack of vocabulary and grammar.

Keywords: writing thesis, personality factor (Internal factor), sociolinguistic Factor and Linguistic Factor (External factor)