Identifying the potential pathways linking childhood abuse to depression and suicidal ideation is critical for developing effective interventions. This study investigated implicit self-esteem—unconscious valenced self-evaluation—as a potential pathway linking childhood abuse with depression and suicidal ideation. A sample of youth aged 8–16 years (N = 240) completed a self-esteem Implicit Association Test (IAT) and assessments of abuse exposure, and psychopathology symptoms, including depression, suicidal ideation, anxiety, and externalizing symptoms. Psychopathology symptoms were re-assessed 1–3 years later. Childhood abuse was positively associated with baseline and follow-up depression symptoms and suicidal ideation severity, and negatively associated with implicit self-esteem. Lower implicit self-esteem was associated with both depression and suicidal ideation assessed concurrently and predicted significant increases in depression and suicidal ideation over the longitudinal follow-up period. Lower implicit self-esteem was also associated with baseline anxiety, externalizing symptoms, and a general psychopathology factor (i.e. p-factor). We found an indirect effect of childhood abuse on baseline and follow-up depression symptoms and baseline suicidal ideation through implicit self-esteem. These findings point to implicit self-esteem as a potential mechanism linking childhood abuse to depression and suicidal ideation.