Youth suicide represents an area of important public and mental health concern. Although diagnostic correlates (e.g., depression) of suicidality have been identified, very few studies of youth have analyzed relationships between empirically-derived dimensions of psychopathology, representing broader dimensions of risk, and different suicidality indicators. We recruited 223 adolescents (57% female; 32% ethnic minority) from mental health agencies and the community to assess psychopathology, substance use, and suicidality relying on multiple measures and reporters (youth, parent, and clinician). Using a 3-factor model of psychopathology, we found that the Internalizing factor (including depression and generalized anxiety) was associated with both suicidal thinking and behaviors (threats/attempts), the Externalizing factor (conduct, oppositional, and attention deficit disorders) was negatively related only to suicidal thinking, and the Substance Use factor (alcohol and cannabis use) related to suicidal behaviors of threats/attempts but not suicidal thinking. The results show the utility of a dimensional conceptualization for clarifying distinct vulnerabilities to suicidal thinking versus overt behaviors and have implications for the construct validity of distinct dimensions of psychopathology.