Objectives: The purpose of this study was to assess the reliability and validity of Swedish translations of the Beliefs about Medicines Questionnaire-Specific (BMQ-Specific) and Brief Illness Perception Questionnaire (B-IPQ) for use in adolescents with ADHD. Methods: Forward and backward translations of the BMQ-Specific and B-IPQ scales to Swedish were conducted and reviewed by adolescents with ADHD and professionals. The validity and reliability of both questionnaires were investigated in a cross-sectional study of 101 adolescents (13?17?years) on a long-term prescription of ADHD medication recruited from two child and adolescent psychiatric outpatient clinics in Sweden. Results: Regarding the BMQ-Specific, principal component analysis (PCA) loadings confirmed the previously defined components of Specific-Necessity and Specific-Concern. The PCA for B-IPQ revealed two components, the first one, B-IPQ Consequences, captured questions regarding perceptions of the implication of having ADHD (items 1, 2, 5, 6 and 8) and the second one, B-IPQ-Control, the perceptions of the capability to manage the ADHD disorder (items 3, 4 and 7). The Cronbach alpha coefficients for BMQ-Specific-Necessity scale was ??=?0.80, for BMQ-Specific-Concern scale ??=?0.75, B-IPQ Consequences ??=?0.74 and for B-IPQ-Control ??=?0.44. Conclusions: The present results prove the Swedish translation of BMQ-Specific and B-IPQ to be valid and reliable for utilization in adolescents with ADHD. The PCA confirmed the original components for BMQ-Specific and the recent findings of two main B-IPQ components describing emotional and cognitive implications versus the capability for self-care maintenance of ADHD.