There is a well-established achievement gap between children from low income families and their middle to high income counterparts. One avenue towards narrowing the achievement gap is improving domain-general school readiness skills, such as motivation, persistence, and preference for challenge which support learning regardless of content area. Motivation orientation, one example of a malleable domain-general construct, encompasses two approaches at opposite ends of a continuum: mastery and performance motivations. The former is characterized by viewing failure as an opportunity for growth, while the latter views failure as a confirmation of a low innate ability level. Interventions targeting motivation orientation have successfully improved academic outcomes in older children; however, attempts to downwardly extend this research to early childhood have yielded mixed results due to the absence of developmentally appropriate measures. This study evaluated a newly developed measure of motivation orientation named the Computer Administered Battery of Observed Motivation (CABoOM) which was specifically designed to be sensitive and appropriate for pre-school children from low-income families. Results suggest that CABoOM is sensitive, test-retest reliable, and response process valid for children served by Head Start. While CABoOM did significantly predict gains in approaches to learning, and science school readiness across the year, the relationships were in the negative directions which is the opposite of the original hypothesis. Further research is required to understand these counterintuitive relationships and provide additional evidence for predictive and concurrent validity. A valid and reliable measure of motivation orientation would allow for evaluation of early childhood interventions aiming to close the school readiness achievement gap by targeting this powerful domain-general skill. (author abstract)