While The Grapes of Wrath highlights specific social and institutional structures that direct the course of action of its main characters, shifting the analysis from structure to agency opens up the novel to new readings. This article considers how Steinbeck's novel problematizes agency and argues that it troubles distinctions between human agency and nonhuman agency. Traditional novels generally rely on the actions of their characters, but in The Grapes of Wrath such action is repeatedly thwarted or fails to lead to the desired outcome. Instead, the characters are acted on through various machines or chains of actors that lead back to a vague and bodiless entity, such as the monster-bank. The novel's emphasis on the tractor, the automobile, the handbill, and the bank provides the basis for my reading, together with more subtle instantiations of material agency as seen in the phonograph, the slot machine, the kerosene, and the sticker displayed on the red truck. Agency has traditionally rested on the notion of free will and intention, but recent theories, such as actor-network-theory, or ANT, highlight material agency and move beyond the subject in favor of networks and distribution of agency. This article uses theories on agency to reread Steinbeck's classic novel, but also attempts to show how Steinbeck's novel can increase our understanding of the concept of agency more broadly.