Considerable research documents students' outcomes in dual language (DL) programs, but there is little examination of students' perceptions of bilingualism and its impact on students' cognitive functioning and social relationships, especially with comparative studies across different target languages and student backgrounds. This study, which included a total of 788 fifth- through eighth-grade students who had participated in a Spanish-English (n = 645) or Mandarin-English (n = 143) dual language program, surveyed students' language proficiencies, ratings of bilingualism, and social and cognitive functioning. Overall, DL students had developed language proficiency skills in both languages, rated themselves as somewhat or very bilingual, enjoyed participating in the program, have positive attitudes toward the languages and speakers of the target language, and perceive some cognitive and other benefits from being bilingual. However, there were significant group differences according to target language, program model (90:10 vs. 50:50), level of bilingualism, and whether students were native target language or English speakers.