There is an ever-increasing need for school psychology training programs to demonstrate their ability to produce competent practitioners. One method of addressing this need is through the assessment of self-efficacy. However, little research on self-efficacy in school psychology exists likely due to the lack of a psychometrically sound measure of this construct. To address this gap, we examined the construct validity of the Huber Inventory of Self-Efficacy for School Psychologists Research Version (HIS-SP-RV), a preexisting measure of self-efficacy, with a sample of 520 school psychology graduate students. Results suggest that the HIS-SP-RV is not a valid measure of trainee self-efficacy. We then created and conducted a psychometric evaluation of a shortened measure, the Huber Inventory of Trainee Self-Efficacy (HITS). Results supported the validity of a five-factor model. Implications for the use of the HITS for program evaluation, to improve trainee competence, and for future research are discussed.