This study examined differences between Costa Ricans and Euro-Americans in perceptions of appropriate sexual behavior and definitions of sex. When compared to Costa Ricans, Euro-Americans were more likely to consider foreplay, oral sex, and intercourse to be appropriate in the early stages of a relationship. Costa Ricans considered these behaviors to be appropriate only after steadily dating someone for 3 months or more. Euro-Americans were more likely to consider anal sex and phone/cyber sex to be appropriate prior to serious commitment (i.e. marriage). Cultural differences were also found in the types of behaviors that were considered to be sex. Costa Ricans defined non-penetrative acts such as foreplay, oral sex, and phone/cyber sex as sex more often than their Euro-American counterparts. In fact, Euro-Americans rarely considered foreplay or phone/cyber sex to be sex and defined oral sex as sex only in certain contexts. Finally, both Costa Rican and Euro-American participants reported having had more lifetime sexual partners than penile–vaginal intercourse partners. Results are discussed in terms of differing cultural values.