OBJECTIVES: Suicide ideation (SI) and suicide attempts (SAs) have been reported as increasing among US children over the last decade. We examined trends in emergency and inpatient encounters for SI and SA at US children’s hospitals from 2008 to 2015. METHODS: We used retrospective analysis of administrative billing data from the Pediatric Health Information System database. RESULTS: There were 115 856 SI and SA encounters during the study period. Annual percentage of all visits for SI and SA almost doubled, increasing from 0.66% in 2008 to 1.82% in 2015 (average annual increase 0.16 percentage points [95% confidence intervals (CIs) 0.15 to 0.17]). Significant increases were noted in all age groups but were higher in adolescents 15 to 17 years old (average annual increase 0.27 percentage points [95% CI 0.23 to 0.30]) and adolescents 12 to 14 years old (average annual increase 0.25 percentage points [95% CI 0.21 to 0.27]). Increases were noted in girls (average annual increase 0.14 percentage points [95% CI 0.13 to 0.15]) and boys (average annual increase 0.10 percentage points [95% CI 0.09 to 0.11]), but were higher for girls. Seasonal variation was also observed, with the lowest percentage of cases occurring during the summer and the highest during spring and fall. CONCLUSIONS: Encounters for SI and SA at US children’s hospitals increased steadily from 2008 to 2015 and accounted for an increasing percentage of all hospital encounters. Increases were noted across all age groups, with consistent seasonal patterns that persisted over the study period. The growing impact of pediatric mental health disorders has important implications for children’s hospitals and health care delivery systems.