The present study examined book-sharing interactions between mothers and their 4-year-old children from African American (n = 62), Dominican (n = 67), Mexican (n = 59) and Chinese (n = 82) low-income U.S. families, and children's independent storytelling skills one year later. Mothers' book-sharing style was analysed in terms of how much storyline information they provided (story components), the extent to which they asked children about the story (dialogic emphasis) and which features of the story they highlighted (story content). African American mothers referred to more story components than did Dominican mothers, and Mexican mothers surpassed Dominican and Chinese mothers. Mothers of all groups were low in dialogic emphasis; they predominantly narrated rather than asked about the story, although Mexican mothers asked relatively more questions than did African American and Dominican mothers. In terms of content, compared with other groups, African American mothers were most likely to emphasize ‘individual goals’, and Chinese mothers were most likely to emphasize ‘negative consequences’. Latino mothers were more likely to emphasize ‘emotions’ than were Chinese mothers. Children's storytelling styles partially mirrored those seen in their mothers. Mothers' dialogic emphasis related to children's contributions to book-sharing, which in turn predicted children's later independent storytelling skills. Copyright © 2014 John Wiley & Sons, Ltd.