This study assessed the outcomes of adapting the culturally-grounded, middle school, substance-use prevention intervention, "keepin' it REAL" ("kiR"), to target elementary school students and to address acculturation. At the beginning of 5th grade, 29 schools were randomly assigned to conditions obtained by crossing grade of implementation (5th, 7th, 5th + 7th, and control/comparison) by curriculum version ["kiR-Plus" vs. "kiR-Acculturation Enhanced (AE)"]. Students (n = 1984) completed 6 assessments through the end of 8th grade. The "kiR" curricula generally appear no more effective than the comparison schools' programming. Students receiving either version of the "kiR" intervention in only the 5th grade report greater increases in substance use than did control students. Receiving the "kiR-AE" version twice (both 5th and 7th grades) has benefits over receiving it once. (Contains 2 tables and 1 footnote.)