This chapter explores the role of photo archives in the making of archaeological knowledge from the mid-nineteenth century to the present day. It discusses, among other topics, their role in the pursuit of objectivity, their connections to nation-building processes, and the challenges and opportunities posed by the digital age. To do so, the chapter draws on a series of conceptual tools developed by several scholars, such as the notion of the “total photo archive,” the “documentary impulse” prompted by the emergence of photography, the conceptualization of photographs as “facts,” and the understanding of archival practices as “collective undertakings.” The chapter analyzes archaeological photo archives in Europe, the United States, and the rest of the world.