The case of bilingualism is a challenge for psycholinguists who aim to understand how the two (or more) languages of a bilingual are represented in the brain, whether they are organized similarly and how bilinguals manage to keep their languages apart. We first review studies that investigate the organization of the two languages in the brain and whether they interfere with each other during access to the lexicon and syntactic representations. In the second part of the chapter, we report neurolinguistic studies that examine cognitive processes and neural perspectives in monolinguals and bilinguals, with a special focus on factors that may influence bilingual language processing such as proficiency and age of acquisition. Finally, in the third part of the chapter we present theories on L2 processing and discuss the studies presented earlier in relation to these theories. In addition, we have extended the sections on lexical access in sentence context and syntactic processing by including recent studies that reflect the flourishing interest for bilinguals’ ability to predict upcoming words online during sentence comprehension.