Retaining an adequate number of volunteers is important to ensure animal welfare organizations can provide critical services to companion animals and members of their community. This study was conducted to examine whether the job demands-resource model (JD-R: Demerouti et al., 2001; Schaufeli & Bakker, 2004), a model commonly used in employment settings, is a useful framework to predict three retention-related variables in animal welfare volunteers: intention to quit, volunteer frequency, and commitment. The JD-R model posits that job demands and job resources are important predictors of burnout and engagement, which themselves are significant predictors of various work outcomes. The study tested this model using 11,430 volunteers across 148 animal welfare organizations. Utilizing structural equation modeling, the study found that organizational constraints, perception of voice, and recognition, were all predictive of burnout. Subsequently, burnout was identified as a predictor of intention to quit and volunteer frequency. Perception of voice and recognition were also identified as predictors of engagement, and subsequently predictive of commitment. Additional analyses revealed the relationship between organizational constraints and burnout was moderated by tenure, suggesting that volunteers with longer tenure were partially protected from the negative consequences of organizational constraints. Thus, results provided evidence that the JD-R model is indeed a useful framework to study the antecedents of retention-related outcomes in animal welfare volunteers. The theoretical and practical implications of these findings are discussed.