There is a growing research interest in a variety of emotions in foreign and second language (L2) classrooms, especially since the introduction of positive psychology. However, research on the ubiquitous emotional experience of boredom is scant. Building on its prevalence and documented deleterious effects, I argue that research on the antecedents for the instigation of boredom is needed. Based on the control-value theory (CVT) of achievement emotions in educational psychology, this study took a mixed methods approach to examine control-value appraisals as antecedents of boredom in English-as-a-foreign-language learning among Chinese university students. In line with CVT assumptions, Pearson correlation analyses and regression analyses (N = 2,002) showed that different control-value appraisals predicted boredom uniquely or interactively. Qualitative data from interviews with 11 students and 11 English teachers expanded the quantitative results by including more complexities in the associations between control-value appraisals and boredom. These findings provide further support for the CVT and help to elucidate the instigation of boredom in the L2 learning context. Directions for future research and implications for L2 educational practice are discussed.