ObjectiveTo compare cause-specific UK mortality in children and young people (CYP) with EU15+ countries (European Union countries pre-2004, Australia, Canada and Norway).DesignMortality estimates were coded from the WHO World Mortality Database. Causes of death were mapped using the Global Burden of Disease mortality hierarchy to 22 cause groups. We compared UK mortality by cause, age group and sex with EU15+ countries in 2015 (or latest available) using Poisson regression models. We then ranked the UK compared with the EU15+ for each cause.SettingThe UK and EU15+ countries.ParticipantsCYP aged 1–19.Main outcome measureMortality rate per 100 000 and number of deaths.ResultsUK mortality in 2015 was significantly higher than the EU15+ for common infections (both sexes aged 1–9, boys aged 10–14 and girls aged 15–19); chronic respiratory conditions (both sexes aged 5–14); and digestive, neurological and diabetes/urological/blood/endocrine conditions (girls aged 15–19). UK mortality was significantly lower for transport injuries (boys aged 15–19). The UK had the worst to third worst mortality rank for common infections in both sexes and all age groups, and in five out of eight non-communicable disease (NCD) causes in both sexes in at least one age group. UK mortality rank for injuries in 2015 was in the top half of countries for most causes.ConclusionsUK CYP mortality is higher than a group of comparable countries for common infections and multiple NCD causes. Excess UK CYP mortality may be amenable to health system strengthening.