Idiom comprehension and production reflect a child's language competence. Research suggests that there is a positive relationship between children's reading comprehension skills and their idiom understanding. This study examines whether adult verbal scaffolding, in conjunction with the deliberate use of iconic gestures, can facilitate young bilingual children's comprehension and retention of idiomatic expressions in their different languages. Twenty-three five-year-old English-Chinese bilingual children learned novel idioms across two experimental conditions. In Experiment 1, a native Chinese-speaking adult and a native English-speaking adult, respectively, taught children a set of Chinese and English idioms via speech only. In Experiment 2, the same adults, respectively, taught a different set of Chinese and English idioms via speech-gesture combinations. The results suggest that children could comprehend more idioms in both languages after being taught via the speech-gesture modality than the speech-only modality. They also tended to retain more idioms taught in the speech-gesture modality than in the speech-only modality in both languages. Moreover, those children who scored high in their idiom comprehension and retention also scored high both in their recast of the gestures used by the adults and in their rate of speech-gesture mismatches. Educational implications for early childhood settings are discussed.