An “object lesson” is more than a timeworn metaphor used to describe a way of reasoning from the concrete to the abstract. From the 1860s onward, object lessons were classroom exercises organized around the study of material things and were popular across the United States. Using items like penknives and whalebone, teachers employed this methodology to teach children how to perceive their material worlds and to use their heightened observational skills to reason, both critically and morally. “Object Lessons in American Culture” links this historic classroom practice to the ways nineteenth-century Americans came to understand the matter that surrounded them. It argues that the systematic study of material things via object lessons shaped the ways adults and children found meaning in their possessions, considered the connections between objects and pictures, and viewed and talked about race and citizenship. Furthermore, this dissertation establishes object lessons as a historical way of learning from and engaging with objects and pictures. The practice of object lessons parallels and prefigures certain aspects of current material culture scholarship, a connection that historicizes material culture methodologies. The dissertation is divided into five chapters. “Through a Window” I) introduces the practice that would become object lesson pedagogy moving from Johann Heinrich Pestalozzis Swiss schoolroom to the antebellum United States. “Thinking with Things at School” II) examines Civil War-era reforms that crystallized European ideas about object teaching into classroom-ready object lesson pedagogy. “Picture Lessons” III) looks at what object lessons on pictures may reveal about nineteenth-century visual culture. “Object Lessons in Race and Citizenship” IV) considers how African American and Native American students were taught via object lessons and simultaneously described and represented as living object lessons. Finally, “Objects and Ideas” V) investigates the ways politicians, advertisers, and authors employed the concept of the object lesson and what their projects may reveal about object-based epistemology at the end of the century. This dissertation explains how object lessons, as pedagogy and metaphor, patterned the ways many nineteenth-century Americans thought about their material worlds.