Nutrition instruction can lead to more healthful food choices among children, but little is known about preschoolers' healthy-meal schemas because there are few developmentally appropriate measures. This study validated the Placemat Protocol, a novel measure of preschooler healthy-meal schemas using realistic food models to assemble pretend meals. Preschoolers (N = 247, mean age 4 years 8 months) created 2 meals (preferred and healthy), completed measures of verbal nutrition knowledge and vocabulary, and were weighed and measured for BMI. Parents reported healthy eating guidance, child dietary intake, and family demographics. Children used an average of 5.1 energy-dense (ED) and 3.4 nutrient-dense (ND) foods for their preferred meal, but reversed the ratio to 3.1 ED and 5.1 ND foods for their healthy meal. Healthy meals contained fewer estimated kcal, less fat, less sugar, and more fiber than preferred meals. Meal differences held for younger children, children with lower verbal nutrition knowledge and vocabulary, and child subgroups at higher risk for obesity. Placemat Protocol data correlated with parent healthy eating guidance and child obesogenic dietary intake as expected. The Placemat Protocol shows promise for assessing developing healthy-meal schemas before children can fully articulate their knowledge on verbal measures.