Objective: A callous-unemotional (CU) subtype of conduct disorder (CD) has been proposed as an addition to the fifth edition of the "Diagnostic and Statistic Manual of Mental Disorders (DSM-5)." This study tested the hypothesis that young girls with the CU subtype of CD would exhibit more severe antisocial behavior and less severe internalizing problems over time relative to girls with CD alone. Second, the developmental outcomes of girls with CU traits in the absence of CD was examined because these girls would be overlooked by the proposed CU subtyping scheme. Method: Theses issues were examined in a community sample of 1,862 girls 6 to 8 years of age at study onset. Outcomes included internalizing and externalizing problems, academic achievement, and global impairment assessed concurrently and at a 6-year follow-up. Results: Girls with the CU subtype of CD had higher levels of externalizing disorder symptoms, bullying, relational aggression, and global impairment than girls with CD alone. Girls with CD alone tended to have more anxiety problems than girls with the CU subtype of CD. Girls with high CU traits without CD exhibited higher ODD and attention-deficit/hyperactivity disorder (ADHD) symptoms and lower academic achievement at the 6-year follow-up relative to girls without CU traits and CD. Group differences at the 6-year follow-up were primarily accounted for by baseline differences on the outcomes. Conclusions: The proposed DSM-5 CU subtype of CD identifies young girls who exhibit lower anxiety problems and more severe aggression, CD symptoms, academic problems and global impairment across time than girls with CD alone. (Contains 2 figures and 6 tables.)