This case study examined the level of reflection in the essays written by 15 Mexican English language teachers taking a Master's Degree course in English as a foreign language (EFL). The essays were evaluated using the categorization scheme for assessing the level of reflection developed by Kember, et al. (2008). Semi-structured interviews were held with information-rich participants to investigate the difficulties experienced with reflective writing and the usefulness attributed to this academic genre. Findings suggest that the categorization scheme is applicable to reflective writing in EFL, although almost half of the participants continued to write in a non-reflective mode throughout the course. Low level of proficiency in English, lack of familiarity with reflective writing, challenges of deductive reasoning, and the absence of productive feedback were their reported difficulties. Reflective writing was deemed useful because it facilitates participation in class discussion, a more thorough completion of course readings, the adoption of a stance towards SLA theories, and improvement of academic writing ability.