This article describes a qualitative study of how two ethnic Burmese families in the United States authored storybooks that included their children's drawings and writings representing their families' stories. The theoretical perspectives of storytelling and the social semiotics multimodal approach were utilized in this inquiry. The data included interviews, video recordings of the storybook-writing process, artifacts, and informal conversations. The data were collected when both families participated in the study together. The findings show that the children took the lead in authoring and composing their storybooks and carefully chose the topics for their drawings and writings and that the process was mediated through their mothers' oral storytelling and conversations with siblings and friends. The findings suggest that schools and teachers need to incorporate multimodal storytelling into class activities and use storytelling to support children's agency.