This paper investigates pragmatic and sociolinguistic factors that condition the use of double negation along the Haitian-Dominican Republic border in the speech of Spanish monolinguals and in that of Haitian Creole/Spanish bilinguals. In Dominican Spanish, researchers have proposed two basic syntactic configurations for negation: a single pre-verbal negative marker of no + verb and a set of configurations that entail double negation. Double negation may involve simultaneous pre- and post-verbal negative markers, preverbal and sentence final negative markers, and a preverbal negative marker plus a negative polarity item such as nada ‘nothing’, tampoco ‘neither/either’, or nadie ‘nobody’. With respect to social groups, two points emerge. First, monolingual speakers of Dominican Spanish show a higher frequency of double negation than do the bilingual Haitian Creole-Spanish speakers. Second, Haitian learners of Dominican Spanish, independent of their degree of proficiency in Spanish, predominantly acquire and use the pattern of single pre-verbal negation. They display very few cases of double negation. Those Haitian speakers who do display some double negation show certain patterns of negation that may be interpreted as transfer from Haitian Creole. However, as these speakers increase in proficiency, they progressively diminish such transfer. Therefore, the relative absence of double negation in the Spanish of the Haitian Creole-Spanish bilinguals and the presence of double negation in the monolingual Dominican Spanish speakers does not provide support for claims that double negation in Dominican Spanish results from contact with Haitian Creole.