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.