This paper examines Thai-English code-switching by eight Thai students at the University of Hawaii at Manoa by taking into account Bell’s audience design factors (Bell 1984), speech accommodation theory (Giles & Smith 1979; Giles & Coupland 1991), and other psychosocial factors. Code-switching is defined here as an alternation between one language and another made by a speaker within a sentence, sentences, or a conversation. This paper proposes that code-switching is essentially an accommodative phenomenon; that is, speakers will switch into one language if they think it is appropriate to the topic or to their notions of self and addressee. Conversely, some speakers appear to actively resist code-switching, depending on their evaluation of their own linguistic skills and their perceptions of others. By bringing together observations about who favors code-switching and who resists it, the topic of conversation, among other factors, emerges as the most important social variable across individuals. The result runs counter to the audience design model proposed by Bell (1984), who claims that audience design factors are more important than non-audience design factors in bilingual code choice.