Introduction: The Group Psychoeducation Program focuses on improving the attitudes towards medication of parents and their children/adolescents (G-PAM) with attention deficit hyperactivity disorder (ADHD). Aim: We evaluated the program’s effectiveness at improving children’s attitudes and identified what aspects required improvement. Method: This non-randomized, pragmatic evaluation had a comparative before-after design. The G-PAM comprised five 90-minute sessions. We assessed knowledge of psychopharmacology and employed several instruments including the Southampton ADHD Medication Behavior and Attitude Scale (SAMBA), Child Adherence Questionnaire (CAQ), and a Client Satisfaction Questionnaire, among others. Results: The intervention group consisted of 15 families (17 children) who participated in the program in 3 groups. The control group consisted of 24 families (24 children). Children in the intervention group showed improved treatment knowledge, a decreased SAMBA score for ‘resistance to medication’, and an increased CAQ score for ‘attitude toward medication’. Parents showed an increased SAMBA score for ‘perceived psychosocial benefits of medication’. Both children and parents reported high satisfaction levels. Discussion: The current psychoeducation program provides a new approach to improve the attitudes and behaviors towards medication of children/adolescents with ADHD and their parents in clinical settings.