Climate change, natural hazards, and human actions are threatening cultural heritage in urban areas. More than ever, building regulations’ procedures and criteria are essential to guarantee the protection and safeguarding of urban areas and their buildings. These procedures and criteria are crucial to assist stakeholders in decision-making, especially when facing rapid transitions and transformative changes in urban heritage areas. Several institutional stakeholders in charge of urban heritage protection strengthen the need for a better implementation of building regulations through flexible criteria to support intervention procedures in buildings with different features and in different contexts. Under this topic, the present study uses a twofold method. Firstly, the authors analyze and compare the urban and building regulations of three Southern European countries, Italy, Spain, and Portugal, concerning procedures and criteria directed to the built heritage; secondly, they highlight and compare the views of different institutional stakeholders from the same three countries, at different levels (national, regional, and municipal), to understand the impact of the implementation of the regulations on the ground. The findings show the relevance of the institutional stakeholders’ views to improve the regulations and their practice. They highlight the need to promote inventory and cataloging procedures, as well as flexible criteria when dealing with urban heritage buildings.