Parenting an adolescent is a challenge anywhere, but is harder still where families face severe poverty and illness. Since 2012, a team from DSPI has been working with UNICEF, the World Health Organisation and Universities of Cape Town, Stellenbosch, Bangor and Reading to develop and test free parenting programmes for low and middle income countries. This tells the story of the Teen programme – which has been adapted and tested over three years and then used in a 40-site cluster randomised trial with 1100 teens and their caregivers. It also discusses the complexity of policy engagement and uptake – with massive international scale-up of the program during the testing stages.