The present study investigated the effect of university students' demotivational status, language learning strategies and learning style preferences on their underachievement in English language learning. To begin, 260 Iranian undergraduate students were selected through the multi-stage cluster sampling method. They were put into two successful and unsuccessful groups using the median of their General English scores. Then, they answered the questionnaires of language learning strategies, styles and demotivation. On the next stage, the data gathered was analyzed via several statistical analyses. The results revealed that the reliability and validity of all three questionnaires calculated using exploratory and confirmatory factor analyses and Cronbach alpha coefficients were satisfactory. Moreover, the results of the logistic regression analysis confirmed that there is a difference between the successful and unsuccessful groups in English language learning regarding their motivational status and learning strategies. However, their learning style preferences were not significant predictors of their achievement in EFL classroom. It was also found that from among all subscales of demotivation and learning styles and strategies, only the Lack of Perceived Individual Competence, the Lack of Intrinsic Motivation, the Inappropriate Characteristics of Teachers' Teaching Methods and Course Contents and the Metacognitive strategies predicted university students' group membership significantly.