This meta-analysis synthesizes research on the relation between patient adult attachment style and patient-rated working alliance. A random-effects model was used to calculate the mean weighted product-moment correlation (r) for 24 studies (12 published in peer-reviewed journals and 12 unpublished doctoral dissertations) of individual outpatient therapy with adults. The mean weighted r for attachment avoidance and alliance was −.137, p<.001, and the mean weighted r for attachment anxiety and alliance was −.121, p<.001. These findings suggest that therapists should attend to attachment in order to foster alliance and have additional implications for theory and future research.