This paper’s primary goal is to propose a methodological strategy to document and protect modern heritage buildings in Riyadh, Saudi Arabia. This is essential because these structures are part of the cultural heritage and identity of Saudi Arabia, considering the rapid urbanization and development taking place. Protecting modern heritage buildings is also essential to increase public appreciation and understanding of modernist architecture and valuable resources of the city’s culture and identity. This study’s objectives fall into two categories: it aims to provide a review of the relevant literature to develop a theoretical framework to examine and document Riyadh City’s significant modern heritage buildings, and it aims to provide an examination and documentation of these structures. To ensure systematic and structured project documentation, quantitative and qualitative methodologies, inductive and deductive approaches, a chronological approach, data management techniques, workshops, and fieldwork methods are utilized. Over 1300 potential modern heritage buildings were identified and categorized into typological groups and building types that historians, architects, planners, designers, and policymakers can use to document and present Saudi Arabia’s rich modern heritage effectively. Of the 1300 buildings, this study was able to identify more than 170 buildings, which were later recognized as the primary modern heritage buildings for Riyadh City in the study timeline (1950–2000).