Research has shown that the potential benefits of a flipped classroom could be diminished by the way students perceive and prepare information prior to class. This study aims to explore individual characteristics, such as learner motivation, self-efficacy and epistemology beliefs, that might have an impact on learning outcomes in a flipped classroom. Data were collected using four instruments during a 7-week flipped classroom conducted from mid-September 2014 to mid-November 2014 with a total enrolment of 85 students (10 females and 75 males) in the required course, Applied English for Vocational Education. After controlling for pre-test and other covariates (eg, gender, grade and experience), an analysis based on structural equation modeling showed a positive and significant (ß = 0.12, p < 0.05) indirect effect of instrumentality (promotion) on the change in test scores through averaged quiz scores. Beliefs had a significant positive effect on change in scores between pre- and post-tests (ß = 0.20, p < 0.05). Findings revealed that language learners with a high level of motivation in instrumentality (promotion) followed quiz mechanisms closely and thus benefited most from the flipped classroom. Learners with high beliefs exhibited improvement in the post-tests without doing well in quizzes. The implications for a flipped language learning classroom are discussed, including multiple strategies for regulating learners of different personal traits to preview the online course content before class.