Maternal sensitivity is of central importance to a child's healthy development. This study examines how different types of psychosocial stress originating from the child, the parents, the context, and overall stress relate to maternal sensitivity. Psychosocial stress and its impact on maternal sensitivity are assessed in an at-risk sample of 248 mother-child dyads in the first half year of life. The cross-sectional study was realized as a part of the ZEPPELIN project in the canton of Zurich, Switzerland. Results show, first, that maternal sensitivity decreases with increased amounts of overall stress. Second, lack of social support and low maternal education is associated with reduced maternal sensitivity. Finally, reduced sensitivity is associated with the combination of severe material and parental/familial stress. In contrast, child stress indicators appear to have a weaker association to maternal sensitivity. Implications of these results for practice are discussed.