Knowledge on the validity of the Strengths and Difficulties Questionnaire (SDQ) among adolescents is limited but essential for the interpretation of SDQ scores preceding the diagnostic process. This study assessed the predictive and discriminative value of adolescent- and parent-rated SDQ scores for psychiatric disorders, diagnosed by professionals in outpatient community clinics, in a sample of 2753 Dutch adolescents aged 12–17. Per disorder, the predictive accuracy of the SDQ scale that is contentwise related to that particular disorder and the SDQ impact scale was assessed. That is, 24 logistic regression analyses were performed, for each combination of DSM-IV diagnosis [4: Attention-Deficit/Hyperactivity Disorder (ADHD), Conduct/Oppositional Defiant Disorder (CD/ODD), Anxiety/Mood disorder, Autism Spectrum Disorder (ASD)], informant (3: adolescent, parent, both), and SDQ scale(s) (2; related scale only, related scale and impact scale). Additional logistic regression analyses were performed to assess the discriminative strength of the SDQ scales. The results show both fair predictive strength and fair discriminative strength for the adolescent- and parent-reported hyperactivity scales, the parent-reported conduct scale, and the parent-reported social and prosocial scales, indicating that these scales provide useful information about the presence of ADHD, CD/ODD, and ASD, respectively. The SDQ emotional scale showed to be insufficiently predictive. The findings suggest that parent-rated SDQ scores can be used to provide clinicians with a preliminary impression of the type of problems for ADHD, CD/ODD, and ASD, and adolescent for ADHD.