Improving youth science comprehension is critical to youth development, yet this intended outcome is often overlooked in terms of how Extension programs are delivered. The purpose of the study reported in this article was to determine through the assessment of potential student growth whether applying features of a youth science comprehension model to an Extension youth development program targeting underserved middle-school youths led to improved student academic achievement. Program delivery incorporating key features of the model resulted in improved scores for youths performing at or below grade level. These results suggest that the model offers a promising tool for improving youth science comprehension through Extension programming.