Purpose: Drawing from the conservation of resource theory and the job demands-resources model, this study examines the bi-directional conflicts of work and family during COVID-19, and investigates the online teaching work-related antecedents and the mechanism shaping emotional exhaustion of teachers in Taiwan. Moreover, this study explores mindfulness in teaching as a possible moderator. Design/methodology/approach: Data for analysis were collected from elementary school teachers via an online survey using a questionnaire comprising well-developed scales. The hypotheses were validated using structural equation modeling. Findings: Results show that only family interfering with work conflict mediates the positive relationship of online teaching job demand with emotional exhaustion and negative relationship of online teaching job resource with emotional exhaustion. Results also evidence that mindfulness practiced by teachers can help them perceive their own feelings and thoughts non-judgmentally in face of job demands. Originality/value: With the growing work-from-home trend, the current study revisits the impact of work demands and resources on work-family conflict, and examines whether Taiwanese teachers' perception towards online teaching would lead to different observations. The path that JD[right arrow]WIF conflict[right arrow]EE is well established in the literature, while COVID-19 brings to light another path JD[right arrow]FIW conflict[right arrow]EE, revealing insight into teachers' cognition and plight during the pandemic.