This study assessed the immediate and short-term outcomes of adapting a culturally-grounded middle school program, keepin' it REAL, for elementary school students. After curriculum adaptation, 10 schools were randomly assigned to the intervention in 5th grade with follow-up boosters in 6th grade; 13 schools were randomly assigned to the control condition, implementing the school's pre-existing substance use prevention programming. Students (n=1566) completed a questionnaire prior to curriculum implementation and follow-up questionnaires toward the end of 5th and 6th grade. The 5th grade kiR curriculum generally appeared no more effective than the control schools' programming in changing students' resistance or decision-making skills; substance use intentions, expectancies, or normative beliefs; or lifetime and recent substance use. Such findings have implications for the age appropriateness of school-based programs.