This study investigated the effects of using a teacher-curated LMOOC on EFL students at a university in Thailand. It also investigated students' attitudes to the LMOOC. Data were collected from a group of nursing students (N = 179) taking a compulsory English course. After taking the midterm exam, the students engaged in a 5-week LMOOC intervention as a supplement to their usual English classes instead of regular self-study materials they had in the first half of the semester. Final examination scores and gains since the midterm were compared. Attitudes to the LMOOC were assessed using a questionnaire and interviews. The students experienced statistically significant score gains in the final exam, with greater gains being evident in the grammar and vocabulary portions of the test. The students also reported generally positive attitudes towards the LMOOC implementation. The findings suggest that an LMOOC, when carefully curated and designed, can be an effective supplemental tool for language learning and may positively affect academic performance. Future studies adopting a quasi-experimental research design are needed to assess the applicability of the findings.