To better understand STEM interest development during adolescence in an urban community, we examined how "STEM Interested" youth differed from disinterested youth and how interest changed over time from age 11/12 to 12/13. We surveyed youth to measure interest in four components of STEM, used cluster analysis to categorize youth based on STEM interest, and examined how interest profiles and pathways differed for several explanatory factors (e.g., parental support, gender). Three STEM interest profiles emerged from the analysis: Stem Interested, Math Disinterested, and STEM Disinterested. Only STEM Disinterested youth lost interest in science, technology/engineering, and mathematics while the remaining 76% of youth remained at least somewhat interested in science and technology/engineering. Girls were just as likely as boys to identify as STEM Interested. Participation in out-of-school STEM activities and positive parental attitudes toward science were significant predictors of persistent STEM interest. Decreases in STEM interest were associated with declines in science self-concept and perceived parental attitudes toward science. Results suggested that declining STEM interest may not be the norm for urban youth. The findings also revealed factors that may influence declining STEM interest and reinforced the importance of out-of-school factors in developing and sustaining STEM interest during adolescence.