This meta-analytic review examines the association between attachment and internalizing symptomatology during childhood, and compares the strength of this association with that for externalizing symptomatology. Based on 42 independent samples (N = 4,614), the association between insecurity and internalizing symptoms was small, yet significant (d = 0.15, CI 0.06∼0.25) and not moderated by assessment age of internalizing problems. Avoidance, but not resistance (d = 0.03, CI −0.11∼0.17) or disorganization (d = 0.08, CI −0.06∼0.22), was significantly associated with internalizing symptoms (d = 0.17, CI 0.03∼0.31). Insecurity and disorganization were more strongly associated with externalizing than internalizing symptoms. Discussion focuses on the significance of attachment for the development of internalizing versus externalizing symptomatology.