Young people with developmental language disorder (DLD) often have poorer mental health compared to those without DLD. However, not all young people with DLD experience such difficulties. Two hundred and eighty-one young people at risk of DLD (45% Female; 53% White British) were identified from a UK based population-cohort. Main caregivers completed questionnaires about their early life (<5 years) and their mental health (at 14 years). Parent-child conflict was revealed to be an early risk factor for all mental health outcomes, at age 14. Additionally, harsh discipline and second-hand smoke predicted worse externalising problems, and gender differences predicted worse internalising problems. Further findings demonstrated that, as the number of risk factors increased, so did the severity of mental health difficulties.