Infant attachment is a key predictor of later socioemotional functioning, but it is not clear how parental responsivity to infant expressive behavior is associated with attachment outcomes. A mid-range model of responsivity holds that both unresponsive and highly reactive parental behaviors lead to insecure and disorganized attachment. We examined the relationship between maternal (and infant) contingent responsivity and attachment in a high-risk sample. Participants were 625 infant-mother pairs from a longitudinal study of children with and without prenatal drug exposure and variable levels of associated social risks. Infant-mother pairs participated in the Face-to-Face/Still-Face paradigm (FFSF) at 4-months and in the Strange Situation Procedure (SSP) at 18-months. A model incorporating both linear and quadratic responsivity effects indicated that mothers who were either very high (reactive) or very low (unresponsive) in responsivity were more likely to have infants with disorganized attachment outcomes. While maternal responsivity was associated with attachment disorganization, no associations between maternal responsivity, and attachment security/insecurity were detected. Infant responsivity to mother was not associated with attachment outcomes. The findings suggest the importance of mid-range levels of maternal responsivity in the development of organized attachment among infants facing high levels of prenatal and social risk.