This mixed two-way experimental, cross-sectional study investigated fast-mapping (FM) of novel nouns and verbs in 63 Persian-speaking toddlers aged 30 months, including 31 late-talking (LT) and 32 typically developing (TD) matched with respect to age and maternal education. Toddlers were classified as LT if they had limited expressive vocabulary or limited two-word combinations. The fast-mapping task included four novel object and action labels and four familiar nouns and verbs. The LT group comprehended and produced significantly lower novel words than the TD group. The LT toddlers received significantly lower scores in the FM of verbs than in the FM of nouns, as well as in novel words production compared with novel word comprehension. These results demonstrate that children with LT behave in word-learning almost the same as children with specific language impairment, confirming the potential risk of later language disorder in children with LT.