The Language Massive Open Online Courses (LMOOCs) is a new platform of computer assisted language learning (CALL); since most LMOOCs witness high dropout rates, empirical evidence on English as a Foreign Language (EFL) learners' motivation to accept and utilize LMOOCs for English language learning is warranted. This study recruited 237 Taiwanese participants with experience in completing at least one LMOOC to answer question items based on the levels of three psychological needs (i.e. autonomy, competence, and relatedness) of self-determination theory (SDT) as well as the Unified Theory of Acceptance and Use of Technology (UTAUT). Partial least squares structural equation modelling (PLS-SEM) was used to explore the structural relationship between the variables of SDT and UTAUT. Additionally, linear modelling was employed to test the moderating effect of motivation on the relationship between the four determinants of UTAUT, behavioural intention, and use behaviour. The results of this study report that autonomy, competence, and relatedness are significant to EFL learners' motivation for using LMOOCs. However, while performance expectancy was not statistically significant to behavioural intention, effort expectancy and social influence were. Moreover, behavioural intention and facilitating conditions were significant to use behaviour, while motivation was a significant predictor of LMOOC use behaviour. However, the moderating effect of motivation was only significant to the relationship between the variables of social influence and behavioural intention.