Introduction: School readiness predicts both school and life success, so measuring it effectively is extremely important. Current school readiness tests focus on pre-academic skills; however, mastery motivation (MM: persistent, focus on trying to do a task) and executive functions (EF: planful self-control) are also crucial. Method: The purpose of the paper is to give an overview of a new, computer-based assessment of MM and EF. Results: We have developed a game-like, computer-based assessment for 3 to 8 year-old children, of MM, EF, and recognition of numbers and letters. The new measures are appropriate for both Hungarian and American cultures. They were engaging for children of this age, and preliminary evidence suggests that they are reliable and valid. Conclusion: The new tasks can be part of assessments of school readiness, and would be useful for school practice as well as researchers. The tasks ascertain the extent to which observed deficits in pre-academic domains are due to MM or EF difficulties. The results will contribute to the development of individualized intervention.