Determining which antecedent variables affect employees' work engagement has always been a concern for both managers and researchers. The present study investigated the effect of workplace democracy on teachers' work engagement and explored the mediating role of job satisfaction and the moderating role of school performance. A two-phase sampling-chosen method was used and a total of 1682 elementary and secondary school teachers in China were asked to complete a survey questionnaire. In addition to identifying descriptive statistics and undertaking group difference analysis, PROCESS macro and bootstrapping approaches were applied. It was found that workplace democracy was positively related to teachers' work engagement both directly and indirectly through job satisfaction. Meanwhile, school performance moderated the relationship between workplace democracy and work engagement. Specifically, workplace democracy was more strongly associated with teachers' work engagement in high-performing schools than in low-performing schools. Thus, teachers' work engagement in elementary and secondary schools need to be improved comprehensively through boosting workplace democracy.