ADHD is one of the most common childhood developmental disorders with a worldwide prevalence ranging from 4% to 12%. Complementary interventions therefore become extremely important to reduce the growing disease burden by augmenting traditional treatments. HAI based interventions show initial promise as one such modality with both theoretical backing and active acceptance among caregivers of children with ADHD. Popular accounts further espouse the benefits of companion animals for ADHD. However, there still remains a critical need for a strong empirical evaluation of the effects of animals on children with ADHD, particularly in primary deficit areas. The rationale behind this research is to understand the effects of animals in ADHD through a key neurobiomarker link which may otherwise remain unsubstantiated, thereby limiting the scope of potential HAI applications for ADHD. Findings from this research will provide data both on the impact of HAI and the possible mechanisms through which HAI may operate, thereby informing a more nuanced exploration of HAI efficacy for ADHD in future research.