Drawing on a sociocultural perspective of genre as a social action situated in a particular context, this study examined the functions and genres of four second-grade ESL (English as a Second Language) children’s English writing at home and at school. The two boys and two girls were born and raised in Canada, speaking English at school and with their siblings, and Cantonese at home with their parents. A total of 67 pieces of school writing and 54 pieces of home writing were collected over a five-week period. Findings show that home writing exhibit a wider range of functions and genres than school writing. The study suggests that teachers should be aware of the value of the writing opportunities and contexts bicultural children have at home and, therefore, incorporate such home experiences into classroom teaching to enrich the process of literacy development.