This study uses data from the UK Millennium Cohort Study to examine the extent to which economic circumstances in infancy and mother's mental well-being are associated with children's cognitive development and behaviour problems at age 3 years, and what part parenting behaviours and attitudes play in mediating these factors. The analyses derived from Structural Equation Modelling show that economic deprivation and maternal depression separately and collectively diminish the cognitive and emotional well-being of children, and part of this diminution emanates from less nurturing and engaged parenting by those with less economic and emotional resources.