OBJECTIVE: To examine the independent and cumulative effects of past-year exposure to several different types of child victimization (peer victimization, witnessing family violence, community violence, sexual assault, and maltreatment) on suicidal ideation in a nationally representative sample of adolescents. DESIGN: The study used 2 waves of longitudinal data from the National Survey of Children's Exposure to Violence. SETTING: Conducted in 2008 and 2010 on the telephone with respondents from the contiguous United States. PARTICIPANTS: National sample of 1186 youth aged 10 to 17 years in wave 1. MAIN EXPOSURES: Peer victimization, sexual assault, witnessing family violence, exposure to community violence, and maltreatment by a parent/caregiver. OUTCOME MEASURE: Self-report suicidal ideation in the past month. RESULTS: Controlling for demographic characteristics, internalizing disorder diagnoses, and wave 1 suicidal ideation, findings showed independent effects of peer victimization, sexual assault, and maltreatment by a parent/caregiver on suicidal ideation at wave 2. The risk of suicidal ideation was 2.4 times greater among youth who experienced peer victimization in the past year, 3.4 times greater among those who were sexually assaulted, and 4.4 times greater among those exposed to maltreatment, relative to children who were not exposed to these types of victimization. Findings also showed substantial effects of polyvictimization (exposure to 7 or more individual types of victimization in the past year), with polyvictims almost 6 times more likely to report suicidal ideation. CONCLUSION: Findings point to the importance of recent victimization in increasing risk of suicidal ideation in adolescents and suggest the need for victimization assessments among all youth who are believed to be at risk for suicidal ideation.