This cross-sectional study attempts to investigate the effects of the Aprender em Parceria (A PAR) programme, an intervention in early childhood education and parenting support in the suburbs of Great Lisbon which aims to increase the educational achievement of disadvantaged children from birth to six-years-old. A quasi-experimental design was used in which children and their families participating in the intervention programme were compared to a comparison group of children who were not participating. The sample consisted of 103 children and their families in the first year (2008), 142 in the second year (2009) and 187 in the third year (2010). Results showed that families and children in the A PAR groups made significantly greater gains in the following areas: social support, pleasure in parenting activities, parent--child joint activities, capacity to interact with their children, able to observe their daily progress, recognise the most important moments of interaction. Children made significant progress in their cognitive and social development.