Research on syntactic priming in typically-developing monolingual children has focused on when abstract syntactic representations first emerge and on which mechanisms can explain syntactic priming effects in acquisition. Much of this work has focused on the English passive (but also dative structures). In this chapter, I explore how syntactic priming data can provide more fine-grained information about children's syntactic representations, what we can learn about the role and representation of interfaces, and how syntactic priming can be used to systematically explore frequency effects in L1 acquisition. In each case, I emphasize how research with different structures and languages can make important contributions in these areas.