Twenty kindergartners (eight boys) with cerebral palsy (CP) and their mothers engaged in a writing activity that required dyads to compose a grocery list containing four items together. Maternal writing supports were observed, including graphophonemic mediation (i.e., support for letter--sound correspondence) and printing mediation (i.e., guidance on letter choice and form). Mothers described their home literacy practices, and children's early literacy skills were assessed. Mothers reported engaging in many literacy activities with their children. They also provided variable levels of printing mediation, low levels of graphophonemic mediation, rarely corrected children's writing errors, and frequently provided physical supports to children during the writing activity. Mothers' reported literacy activities at home as well the ways in which they helped children choose letters were strongly related to children's literacy skills. Findings suggest that mothers can bolster their children's literacy skills through carefully orchestrated writing activities when children have CP.