In this cluster randomized effectiveness trial, pediatric primary care practices will be recruited from the American Academy of Pediatrics' national Pediatric Research in Office Settings (PROS) practice-based research network, as well as the client database of the Physician's Computer Company (PCC) - an Electronic Health Record (EHR) vendor. We will recruit 18 practices. 9 practices will be randomized to the Intervention arm and 9 practices to Usual Care. Intervention arm practices will select 1-2 pediatric clinicians to receive in-person training in Motivational Interviewing (MI), behavioral therapy, billing and coding, and study procedures. Usual Care practices will select 1-2 pediatric clinicians to receive billing / coding and study protocol training only, via telephone and webinar; they will be offered in-person MI training at the close of the trial. Around 316 parents of overweight or obese children (BMI > 85th percentile for age and gender) between 3 and 8 years of age at baseline that are patients of participating Intervention arm clinicians will be enrolled. Over 24 months, these parents may receive up to 4 in-person, MI-based counseling sessions with a trained pediatric clinician and up to 6 telephone counseling sessions with an MI-trained Registered Dietician (RD). There will be no study-specific contact with parents or their children in Usual Care practices during the trial - they will continue to receive usual care. EHR and billing data for all 3-8 year old children within all participating practices will be extracted by PCC to permit determination of the effectiveness of the intervention versus usual care on change in BMI z-score among 3 groups: 1) all eligible children in the Intervention arm), 2) all eligible children whose parent actively participates in the trial , and 3) all 3-8 year old children in all participating practices.