Introduction: With nationwide movement toward an integrated medical home, evidence to support, compare, and specify effective models for collaboration between primary care and behavioral health professionals is essential. This study compared 2 models of primary care with behavioral health integration on American Academy of Pediatrics guideline adherence for attention-deficit/hyperactivity disorder (ADHD) assessment and treatment. Method: We conducted a retrospective chart review of a random sample of children aged 6–13 years, seen for ADHD services in 2 primary care offices, 1 fully integrated model and 1 co-located service only model, comparing ADHD assessment and treatment practices. We used chi-square analyses and logistic regression modeling to determine differences by type of health care model. Results: Among children with ADHD (n = 149), the integrated care model demonstrated higher rates of guideline adherence, more direct contact with schools, and more frequent behavioral observation during clinical encounters. Families in the integrated practice received more caregiver education on ADHD, behavioral management training, and school advocacy, however, these associations did not remain after accounting for variance associated with onsite engagement with a psychologist. Practices were equivalent on use of medication and psychiatric consultation, although, more families in the integrated practice engaged with a psychologist and attended more frequent medication follow-up appointments than those in the co-located practice. Discussion: This study is among the first to compare different levels of collaborative care on practice procedures. Understanding how we can best integrate between behavioral health and primary care services will optimize outcomes for children and families.