Cross-linguistic effects in successive childhood bilingualism have received increased attention in the last few years. The goal of this special issue is to bring together studies that investigate cross-linguistic influence in child second language (L2) learners by examining how first language (L1) and L2 properties develop and interact in the context of child L2 acquisition. Specifically, the articles in this special issue address the following questions: (a) What is the role of cross-linguistic influence at the syntax-discourse interface? (b) How do target language properties influence L2 developmental paths? (c) Does the L2 influence the L1 when acquiring a syntax-semantics interface phenomenon? (d) What does cross-linguistic influence look like in the context of atypical bilingual acquisition? These questions are answered in the context of diverse child L2 populations growing up in different acquisition settings and with varied degrees of exposure to the two languages.