Our purpose was to examine associations between maternal caregiving and child indicators of toxic stress among multiethnic, urban families with children of early school age. We conducted an exploratory cross-sectional analysis of 54 maternal-child dyads. Mothers reported on parenting behaviors and parental reflective functioning (PRF). Child indicators of toxic stress included hair/salivary biomarkers, anthropometric characteristics, and maternally reported health and behavior. Hostile/coercive parenting behaviors were associated with child externalizing behavioral problems (r = 0.43, p = .001, but lower interleukin (IL) 6 levels (r = 0.31, p = .03). High PRF was associated with fewer child emergency department visits (ρ = -0.43, p = .009), whereas impaired PRF was associated with more behavioral problems (ρ = 0.52, p < .0001). PRF and supportive parenting behaviors may protect against toxic stress among vulnerable families, but additional research is needed to better understand these relationships. Resources are available to help clinicians screen for family risk factors and model responsive caregiving in pediatric settings. Copyright © 2018 National Association of Pediatric Nurse Practitioners. Published by Elsevier Inc. All rights reserved.