Two studies investigated syntactic productivity in three-year-old Mandarin speakers' use of verbs in the SVO and S"ba"OV constructions. In Study 1, children were taught novel verbs in one construction and assessed for their production in the other construction. Children produced verbs taught in the "ba" constructions in SVO utterances, but showed order effects when producing verbs taught in SVO constructions in ba utterances. In Study 2, children described animated scenes either with structural priming (i.e., after hearing verbs in SVO or "ba" constructions). Children demonstrated structural priming, producing more SVO and "ba" utterances, respectively, directly after hearing verbs in these constructions. These results indicate that Mandarin speaking three-year-olds demonstrate productive knowledge of both SVO and S"ba"OV constructions. Their ability to override the predominant input frequency of SVO runs counter to a purely usage-based account of early acquisition of grammar.