Since bilingualism is more common worldwide than monolingualism, studying how bilinguals process language providesan important insight into how the brain processes language in general. Although often neglected in research, early-learnerbilinguals (who learn both languages before adolescence) have important differences compared to bilinguals who learntheir second language later in life (Kim, Relkin, Lee, & Hirsch, 1997). We compared early- and late-learner Spanish-English bilinguals in an eyetracking experiment to investigate how the developmental timing of second language onsetaffects phonological competition between languages. For example, when instructed to click the peanut, late bilingualsfrequently looked at the pineapple, because its name in Spanish (pia) is phonologically similar to peanut. By contrast, theearly bilinguals showed no statistically significant competition effects between their two languages. This study aims toreveal the extent to which second language onset affects competition between languages.