This mixed-methods study considered the effects of ethical philosophy programming at a high-performing, high-poverty urban high school upon the academic integrity of participating adolescents ("n" = 279). Analyses of pre-post survey data revealed that participating adolescents reported significantly higher levels of academic integrity than their peers at a matched comparison school. Field notes from observations of ethical philosophy lessons and qualitative interviews with participating students revealed that this programming offered students frequent opportunities to practice moral reasoning and introduced philosophical perspectives that influenced students' conception of and commitment to academic integrity. (Contains 2 tables and 3 footnotes.)