Objective This study aimed to deepen our understanding of the interpersonal facilitators of posttraumatic growth (PTG) among suicide‐loss survivors (SLSs) by focusing on the effects of attachment models on PTG in a 4‐year longitudinal design. Method One‐hundred and fity‐two SLSs completed a series of questionnaires tapping attachment models, self‐disclosure, social support and PTG in a three‐wave study design. Results Attachment models, self‐disclosure, and perceived social support at T1 were found to predict PTG levels at T2. Self‐disclosure alone predicted PTG at T3. Structural equation modeling analysis revealed that interpersonal factors served as mediators of the relationship between attachment models and PTG beyond the PTG trajectory. Conclusions Attachment models play an important role in facilitating PTG among SLSs. Thus, therapeutic interventions based on attachment models of self and other specifically designed to promote a sense of self‐worth and confidence in others may be valuable in facilitating growth among SLSs.