This study was designed to explore patterns of student perceptions of second language (L2) classroom environments and the relationships between such perceptions and L2 willingness to communicate (WTC). A sample of 845 first-year undergraduate students of English as a foreign language (EFL) participated in the study and reported their perceptions of the L2 classroom environment and their WTC. Using cluster analysis, this study aggregated students’ perceptions of the classroom environment into four clusters: High support, Rapport, Input, and Low support classes. These four clusters of classes differed significantly in the student perceived support of interpersonal relationships and instructional input. A one-way ANOVA further showed that L2 WTC was positively related to student perceptions of interpersonal relationships and instructional input. More specifically, students’ positive perceptions of interpersonal relationships tended to facilitate WTC in meaning-focused activities, while students’ positive perceptions of instructional input tended to facilitate WTC in form-focused activities. This study finally proposed a model to depict perceived situation cues as antecedents (interpersonal relationship and instructional input) of L2 WTC. Implications for L2 instruction and learning were also discussed.