Objectives: Approximately 30% of children diagnosed with attention-deficit/hyperactivity disorder (ADHD), the most prevalent mental health disorder in children worldwide, do not respond to conventional pharmaceutical treatments. Previous studies of homeopathic treatment for ADHD have been inconclusive. The objectives of this study were to determine if there (a) is an overall effect of homeopathic treatment (homeopathic medicines plus consultation) in the treatment of ADHD; (b) are any specific effects the homeopathic consultation alone in the treatment of ADHD; and (c) are any specific effects of homeopathic medicines in the treatment of ADHD. Design: The design was a randomized double-blind placebo-controlled clinical trial. Setting/Location: Toronto, Canada. Subjects: Children aged 6–16 years diagnosed with ADHD. Interventions: Participants were randomized to one of three arms: Arm 1 (Remedy and Consultation); Arm 2 (Placebo and Consultation); or Arm 3 (Usual Care). Outcome Measures: Primary Outcome was the change of CGI-P T score between baseline and 28 weeks. Results: There was an improvement in ADHD symptoms as measured by the Conner 3 Global Index-Parent T-score in the two groups (Arms 1 and 2) that received consultations with a homeopathic practitioner when compared with the usual care control group (Arm 3). Parents of the children in the study who received homeopathic consultations (Arms 1 and 2) also reported greater coping efficacy compared with those receiving usual care (Arm 3). There was no difference in adverse events among the three study arms. Conclusions: In this study, homeopathic consultations provided over 8 months with the use of homeopathic remedy was associated with a decrease in ADHD symptoms in children aging 6–16 years when compared with usual treatment alone. Children treated with homeopathic consultations and placebo experienced a similar decrease in ADHD symptoms; however, this finding did not reach statistical significance when correcting for multiple comparisons. Homeopathic remedies in and of themselves were not associated with any change in ADHD symptoms.