The first aim of this study was to construct/validate a subscale--with cut-offs considering gender/age differences--for the school-age Child Behavior CheckList (CBCL) to screen for Autism Spectrum Disorder (ASD) applying both data-driven (N = 1666) and clinician-expert (N = 15) approaches. Further, we compared these to previously established CBCL ASD profiles/subscales and DSM-oriented subscales. The second aim was to cross-validate results in two truly independent samples (N = 2445 and 886). Despite relatively low discriminative power of all subscales in the cross-validation samples, results indicated that the data-driven subscale had the best potential to screen for ASD and a similar screening potential as the DSM-oriented subscales. Given beneficial implications for pediatric/clinical practice, we encourage colleagues to continue the validation of this CBCL ASD subscale.