--- - |2 Using clinically relevant research methodology, this study focuses on differences (cross‐partner difference scores) in perceptions of attachment behaviors (emotional accessibility, responsiveness, and engagement) between partners in couples therapy. In general, findings suggest that higher levels of self‐enhancement attachment behaviors (participant perceives self as demonstrating more attachment behaviors than the partner's ratings of the participant) are associated with lower relationship satisfaction and greater relationship instability. The association between attachment behavior difference scores and measures of relationship health is mediated through partner perceived positive communication. These results suggest that differences in perceptions between partners’ level of attachment behaviors are an important clinical construct for therapy. As such, clinical recommendations for addressing self‐enhancing attachment behaviors, and the mediating role of positive communication, are discussed with recommendations for researchers. - Journal of Marital and Family Therapy, Volume 44, Issue 4, Page 624-639, October 2018.