The purpose of this article was to explore how family chaos, parenting processes, parent-child relationship qualities, and sibling relationship qualities changed before versus the early months of the COVID-19 pandemic. Participants included one parent and two adolescent-aged children from 682 families (2,046 participants). Parents and youth participating in an ongoing longitudinal study in five Midwestern states in the United States completed an additional web-based assessment of family processes and family relationship qualities during the May-June 2020 pandemic-related shutdowns. A series of two-wave latent change score models indicated that family chaos increased with the onset of pandemic-related shutdowns and that the level of chaos within a family during the shutdowns had implications for changes in several parenting processes and family relationship qualities. Specifically, higher levels of family chaos during the pandemic mitigated observed increases in parental knowledge and were associated with declines in parental autonomy granting. Family chaos during pandemic-related shutdowns also was associated with increases in maternal-child conflict, paternal-child conflict, and sibling conflict as well as decreases in paternal-child intimacy, sibling intimacy, and sibling disclosure. Overall, consistent with a family stress perspective, the onset of the COVID-19 pandemic was associated with increased strain and commotion within many households, and these changes had implications for multiple family relationships.