To examine childhood gender nonconformity (GNC) and psychological well-being in a community-based sample using measures that bridge clinical and nonclinical literature. Caregivers reported on the GNC (Gender Identity Questionnaire for Children [GIQC]) and behavioral and emotional problems (Child Behavior Checklist [CBCL]) of their children aged 6 to 12 years (N= 1719, 48.8% boys). The GIQC was compared to the commonly used single-item proxy, CBCL Item 110 ("wishes to be of the opposite sex"). Using the GIQC, 2.3% of boys and 2.8% of girls showed GNC levels comparable to those of children referred clinically for gender dysphoria (GD). Item 110 was endorsed for 1.7% of boys and 1.8% of girls. These measures corresponded, but Item 110 endorsement was biased toward more extreme GNC. Among boys, increased GNC on the GIQC, but not Item 110, corresponded with increased clinical-range CBCL problems. Among girls, Item 110 endorsement was associated with increased clinical-range Externalizing problems, whereas the GIQC indicated that intermediate gender expression was associated with fewer externalizing problems. Overall, rates of clinical-range CBCL problems among GNC children were consistent with those reported for GD-referred children. The scope of mental health risk among community children who exhibit GNC is likely considerably greater than previously recognized. A substantial minority of community children show GNC and mental health risk levels comparable to those seen among GD-referred children. Also, compared to the GIQC, a more comprehensive GNC measure, CBCL Item 110 is likely useful only for detecting extreme manifestations of GNC, which may affect associations with mental health.