Urbanization, industrialization, and globalization have brought about changes in the built environment. Internal migration in the city and the rapid increase in urban population have led to inadequate housing to meet the need for shelter and created a housing deficit and need. One of the measures taken to meet this need was the emergence of mass housing production. Increasing qualitative satisfaction with the house and its surroundings creates the necessary environment for living in which people enjoy life, are happy, and have greater spiritual satisfaction. In determining quality, user satisfaction, which constitutes user perception and criticism, is the main determinant of quality. Iran and Turkey are countries where mass housing production is increasing. When studies on mass housing in these two countries are reviewed, it is observed that there are not enough scientific studies to analyze user expectations and satisfaction. The research method is descriptive-analytical and is applied in terms of purpose; the aim of which was to determine and reveal the factors affecting user satisfaction in mass housing projects in Iran and Turkey. The data collection tool (questionnaire) was prepared in line with the identified factors. Four selected Toki housing sites in Balikesir province in Turkey and 2 sites of Mehr housing in Iran were surveyed. User expectations, quality of built components and other factors determining the level of satisfaction were compared. The results of the study show that there is a relationship between the identified factors and user satisfaction. The fact that there are factors that increase this satisfaction is confirmed by the data obtained from the survey results.