This study examines whether lexical repetition, syntactic skills, and working memory (WM) affect children's syntactic-priming behavior, i.e. their tendency to adopt previously encountered syntactic structures. Children with Specific Language Impairment (SLI) and typically developing (TD) children were primed with prenominal (e.g. "the yellow cup") or relative clause (RC; e.g. "the cup that is yellow") structures with or without lexical overlap and performed additional tests of productive syntactic skills and WM capacity. Results revealed a reliable syntactic-priming effect without lexical boost in both groups: SLI and TD children produced more RCs following RC primes than following prenominal primes. Grammaticality requirements influenced RC productions in that SLI children produced fewer grammatical RCs than TD children. Of the additional measures, WM positively affected how frequently children produced dispreferred RC structures, but productive syntactic skills had no effect. The results support an implicit-learning account of syntactic priming and emphasize the importance of WM in syntactic priming tasks.