This paper considers the issue of child agency in Mildred D. Taylor's 1976 novel "Roll of Thunder, Hear My Cry" using a critical corpus linguistics framework based on Halliday's systemic functional linguistics. The novel has long received praise for its portrayal of child agency in a hostile racist society as well as its depiction of a strong African American family with the capacity to bring about change. By charting linguistic features associated with agency, it is possible to examine character development and ideology within the text, and to arrive at conclusions which both support and interrogate existing literary criticism on Taylor's work, with a particular focus on Cassie Logan, considering the role of the child witness-narrator/character and her development over the course of the novel. This methodological framework provides new insights on a classic children's text, while also bringing to the foreground issues of cultural bias in text analysis. This study provides support for Kelly McDowell's suggestion of a "culturally specific agency" in "Roll of Thunder", as well as expanding on this idea.