As contemporary organizations are met with increasing demands and uncertainty, their continued success relies on employees' willingness and ability to think proactively and take action in the face of challenges. Some scholars have reasoned that stressors in the work environment may serve as indicators, to employees, that change is needed, therefore promoting proactive work behavior. However, current theories related to work stress assert that demands in the environment may exert effects dependent on the degree to which resources are available to cope with demands. Drawing on the Job Demands-Resources model and others, the present research examines the interplay between psychological resources, work stressors, and proactive work behavior in a sample of 229 preschool teachers in Germany. Specifically, the focus is on the moderating role of state-level psychological resources (eg, enthusiasm, self-assurance, attentiveness, and feeling recovered) in the relationship between work stressors and proactive work behavior. Data was collected at three time points and included both self-and co-worker reports of proactive work behavior. Results indicate that psychological resources, characterized by positive mood and high energy, play an important motivational role in the face of work stressors. Findings support the importance of considering individual factors (eg availability of psychological resources) when examining relationships between environmental factors and proactive behavior. Implications for future research are discussed.