Purpose: To examine associations between preschoolers' diet quality and parent and child socio-demographic variables.Methods: Cross-sectional analysis with 117 preschoolers. Parents reported socio-demographics and their children's diet using 3-day food records. Diet quality was assessed using the Healthy Eating Index (HEI) 2015. Linear regression models were used to analyze associations between socio-demographics and HEI scores.Results: A total of 86% of children had an HEI-2015 score in the "needs improvement" category (51-80 out of a maximum of 100). Children's overall HEI-2015 score was inversely associated with children's age (β = -0.19, 95% CI -0.37, -0.02). Parental education was positively associated with children's overall HEI score (β = 9.58, 95% CI 3.81, 15.35) and with scores for total fruit (β = 1.00, 95% CI 0.39, 1.76), vegetables (β = 1.11, 95% CI 0.03, 2.18), total protein (β = 1.06, 95% CI 0.28, 1.84), and seafood/plant protein (β = 1.67, 95% CI 0.43, 2.89) components. Children who identified as Caucasian (β = 4.29, 95% CI 2.46, 6.14), had a Caucasian parent (β = 3.01, 95% CI 0.78, 5.25), or parents who were born in Canada (β = 2.32, 95% CI 0.53, 4.11) had higher scores for dairy.Conclusion: Our results suggest that preschoolers' diet quality needs improvement and that children's diet quality varies by children's age and parental education level.