This paper reviews current research findings on how specific learning difficulties (SLDs) impact on the processes of multilingual language development. The review includes studies of young language learners in instructed classroom settings as well as of multilingual children in second language contexts. The paper starts with a definition of the concepts of disability and SLDs. Next, it discusses the interaction of cognitive factors with L1 and L2 literacy development and L2 learning. The paper also outlines possible ways in which SLDs can be identified in different L2 learning contexts. A detailed analysis of how cognitive factors influence the development of second language skills of young learners with learning difficulties is given in the last part of the paper.