Although more than 2 million service members have experienced deployment since 2001, predictors of postdeployment family functioning remain unclear. Utilizing the Contextual Model of Family Stress (Boss, 2002), this study examined military‐related factors (e.g., rank, component, combat exposure, postdeployment time at home, cumulative length of deployments), boundary ambiguity, and family‐ and deployment‐related ambivalence as predictors of family functioning during reintegration. Service members (N = 228) from multiple branches of the U.S. military participated in a national survey related to family relationships and support programming. Hierarchical regression analyses revealed that service members from lower ranks, who were home for longer periods of time, and who endorsed higher degrees of boundary ambiguity and family‐related ambivalence reported poorer family functioning. Results emphasize the relevance of boundary ambiguity and family‐related ambivalence to the reintegration process and can inform prevention and intervention efforts that promote family well‐being in the military population during the critical postdeployment period.