This study of 52 predominantly lower income Jordanian and Syrian families with young children (31 girls; M_age  = 53.37 months, SD = 3.53) in Jordan began in 2019, before the pandemic. Families were followed to explore stress physiology, family functioning, and mental health over the first 9 months of the pandemic. Mothers reported less adaptive coping and more negative changes to family life in June 2020 when their children had poorer behavioral self-regulation and more behavior problems, and when families had lower income, in 2019. More negative changes to family life predicted greater hair cortisol concentrations in children in June 2020, and more negative changes and less adaptive coping predicted worse child and mother psychosocial adjustment in December 2020.