This study aimed to investigate the current status of and interrelationships among elementary school teachers’ professional learning communities, positive psychological capital, and teaching innovation. The research methods included a questionnaire survey. The survey subjects were public national elementary school teachers in Taiwan. The data were analyzed by descriptive statistics, correlation analysis, the bootstrap method, and structural equation modeling (SEM). The results showed that teacher perceptions of teachers’ professional learning communities, positive psychological capital, and teaching innovation had significant positive correlations among the three variables. In addition, teachers’ professional learning communities had a significant direct effect on teaching innovation, and this effect was enhanced in extent and in magnitude when mediated by positive psychological capital. Based on the conclusions, this study had a number of suggestions: 1) schools should provide enough space and time for discussion, so as to improve the supportive environment of the teachers’ professional learning communities; 2) administrative support and professional sharing should be strengthened, so as to enhance teachers’ positive psychological capital; 3) a quality teaching reward system should be created and observations should be practiced to enhance innovation in teaching philosophy; and 4) teachers’ professional learning communities can enhance teachers’ teaching innovation by strengthening the positive psychological capital of teachers’ self-efficacy, hope, optimism, and resilience.