The interior at the margin: the role of gender in the process of professionalizing Interior Design analyzes the process where Decoration, an activity originally domestic, amateur and, crucially, feminine was transformed in a new discipline and profession known today as Interior Design. This process, which occurred between the last decades of the 19th century and the first decades of the 20th century, was a result of the incorporation of technical innovations and values of Modernism in Architecture and Design. It was also directly influenced by other aspects of modernity, such as the distinction between the public and private spheres, urbanization, mass production, and emerging consumer habits. Crucially, this process was also marked by strategies to legitimize the professional status of the activity that had gender discrimination as its core. Based on the observation that the (relatively few) existing publications on the subject based a History of Interior Design exclusively in its points of contact with Architecture and in iconic modern male architects, this research analyzes and emphasizes the contribution of women to this process. In search of a feminist and feminine approach to the History of Interior Design, the importance of the contribution of women from non-professional places of production is highlighted, as well as the trajectories of professionals who have succeeded in the area despite the opposition offered by gender stereotypes.