Background. The Standards for Computer Science (CS) Teachers include indicators related to classroom practices. To assess teacher proficiency related to these indicators at scale, we created and pilot-tested a vignette-based measure of K-5 CS teacher proficiencies related to Standards 2, 4, and 5. Research Questions. Our two research questions were: 1) How difficult did teachers find the new measure, and how effectively did each item discriminate between high- and low-performers? 2) Which teacher characteristics predict scores on the new measure? Methodology. Our team developed three vignettes and carefully aligned associated questions to Standards 2, 4, and 5. After cognitive interviews with K-5 teachers and several rounds of revision, we pilot tested the instrument with 111 U.S. K-5 teachers. Couched in classical test theory, we assessed the measure’s reliability, and each item’s difficulty and discrimination values. We also collected preliminary evidence of validity. Key Findings. Scores on the measure were approximately normally distributed. Item difficulties ranged from .46 (somewhat difficult) to .95 (very easy). Item discrimination values ranged from .16 to .48. Cronbach’s alpha (𝛼 = .66) indicated the measure could be improved to increase reliability. Scores on the measure were positively correlated with teachers’ reported teaching awards, but were not predicted by any of the independent variables. Implications. This new measure of teacher proficiencies shows promising psychometric qualities, though additional revisions to the items are warranted. Once finalized, this measure could be used by practitioners to identify strengths and growth areas for future professional development.