The EZ-Yale Personality Motivation Questionnaire (EZPQ) was used to measure motivation as a facet of school readiness in a sample of 133 children during the spring of their final year of Head Start. Three motivational constructs assessed by the EZPQ, academic mastery motivation, negative reaction tendency, and outerdirectedness, were associated with criterion measures of cognitive and social-emotional school readiness in the expected directions. The EZPQ scales were also sensitive to amount of time spent in Head Start. Children completing their second year of Head Start evinced more adaptive motivational characteristics than children who had been in the program for just one year. Implications address the value of comprehensive definitions of school readiness not restricted to just emergent literacy, math, and language skills. (Contains 6 tables, 1 figure, and 1 footnote.)