The relationship among acculturation-related variables, past sexual activity, and subsequent sexual behavior was examined for a sample of Latino youth in the United States over a 12-month period. A subsample from the National Longitudinal Study of Adolescent Health database was analyzed by means of a prospective design. History of sexual intercourse predicted subsequent sexual behavior over the ensuing 12 months. The acculturation-related variables were related to whether an adolescent reported being sexually active at Wave 1 but in a complex fashion. Among recent immigrants, youth from English-speaking homes were less likely to be sexually active than those from Spanish-speaking homes. The opposite was observed for youth who were born in the United States or who had resided in the United States most of their lives.