Employee voice behaviors are critical to enhanced organizational success. The current study applies self-determination theory (SDT) and the job demands-resources model (JD-R) to examine the relationships among job autonomy, work engagement, and voice behaviors and investigates the moderating role of person–organization fit (P-O fit) on these relationships. A total of 262 full-time employees from various industries (e.g., manufacturing, construction, financial, service, and education industries) in Taiwan completed questionnaires across two time points. The results demonstrated that job autonomy was positively related to promotive voice behavior through work engagement. Additionally, P-O fit strengthened the direct effect of work engagement on promotive voice behavior and the indirect effect of job autonomy on promotive voice behavior through work engagement. Theoretical and practical implications are discussed.