The objective of this study was to examine generational status differences in the longitudinal associations between early parent-child sex communication, dating behaviors, and subsequent sex initiation, as mediated by perceived peer norms, attitudes, and intentions among Latina/o adolescents. Using data from the Healthy PassagesTM project, Latina girls (n = 879) and Latino boys (n = 885) who were identified as 1st- (18%), 2nd- (58%), and 3rd- (24%) immigrant generational status reported on their dating behaviors and parent-child communication about sex at 5th grade (M age = 11.12), their perceived peer norms, attitudes, and intentions regarding sex at 7th grade (M age = 13.11), and if they had initiated sexual intercourse at 10th grade (M age = 16.06). Third-generation Latina girls were more likely than 1st- and 2nd-generation Latinas to have initiated sexual intercourse by 10th grade. Dating behaviors had a positive association with sex initiation for all generational status groups among Latino boys, but only among 1st-generation Latina girls. Moreover, mediating decision-making processes of peer norms, attitudes, and intentions differed for each group. Results demonstrate that pre-adolescent behaviors appear to have long-term influence on an adolescents’ sexual behaviors. Acculturation differences may contribute to different ways in which adolescents decide to engage in sexual intercourse based on previous dating experience.