Despite research demonstrating the importance of language comprehension to later reading abilities, curriculum-based measures to assess language comprehension abilities in preschoolers remain lacking. The Assessment of Story Comprehension (ASC) features brief, child-relevant stories and a series of literal and inferential questions with a focus on causal and predictive inference skills surrounding the main story grammar components and a novel vocabulary word. Following an overview of the iterative development process and pilot studies, this article presents preliminary evidence of the fidelity of administration, reliability of scoring, alternate form reliability, and validity of the ASC. In all, 237 preschoolers, ages 3 to 5 years old, participated in this study. Fidelity of administration and scoring reliability averaged over 90%. Concurrent validity with two established language measures revealed correlations ranging from 0.67 to 0.81. Test-retest reliability and internal consistency also indicated high levels of reliability for this new tool; however, alternate form reliability results suggest further work is needed. Preliminary results indicate that the ASC holds promise as a viable curriculum-based measure that early childhood educators can use for monitoring preschoolers' progress in language comprehension.