Although the career benefits associated with professional networking are relatively well established, the repercussions of this highly regarded career management activity for voluntary turnover have rarely been examined. Given the potential costs associated with voluntary turnover, this study sought to clarify the roles of networking behaviors in relation to voluntary turnover by focusing on the distinction between internal and external networking. Based on survey responses of industrial and organizational psychology professionals, we found that internal and external networking behaviors differentially predicted decisions to voluntarily leave employers 2 years later: The likelihood of voluntary turnover was negatively predicted by internal networking and positively predicted by external networking. Furthermore, to shed light on the reasons why employee networking behaviors differentially predicted turnover decisions, this study also examined 4 turnover antecedents (job satisfaction, job embeddedness, perceived employment opportunities, and job offers) as potential mediating mechanisms. Results revealed that the relationships of internal and external networking with voluntary turnover were mediated by job embeddedness and job offers, respectively. We discuss the implications of these findings for understanding and managing employee networking and retention.