Background Although identified as a significant public health concern, few studies have examined correlates of suicide risk in school‐aged children. Recent studies show a relation between sluggish cognitive tempo (SCT) symptoms and a range of adverse outcomes linked to suicidal ideation, including depression, emotion dysregulation, lowered self‐esteem, and peer problems/social withdrawal, yet no study to date has examined SCT in relation to suicide risk. Methods We tested the hypothesis that SCT would be associated with suicide risk in a sample of 95 psychiatrically hospitalized children (74% male; 62% black) between the ages of 8 and 12 (M = 10.01, SD = 1.50). Parents completed measures of their child's psychiatric symptoms, including SCT and depression, as well as a measure of their own psychopathology. Children completed measures assessing loneliness and depression. Both parents and children completed measures of suicide risk. Results White children reported greater suicide risk than nonwhite children. After controlling for demographic characteristics, loneliness, parental psychopathology, and correlated psychiatric symptoms, including both parent‐ and child self‐reported depressive symptoms, SCT remained uniquely associated with children's suicide risk. Results were consistent across both parent and child measures of suicide risk. Conclusions This multi‐informant study provides strong preliminary support for an association between SCT symptoms and suicide risk in psychiatrically hospitalized children, above and beyond loneliness, depression, and demographic characteristics. Findings are discussed in the context of the interpersonal theory of suicide. Additional studies are needed to replicate and extend these findings, with a particular need for studies that examine the cognitive processes and daydreaming content of individuals displaying elevated SCT symptomatology.