Qajar era is the period of fundamental changes and the introduction of new urban concepts. Squares, a type of urban space, were the subject of some of these changes. This article focuses on four main Qajar capital squares (Mashgh, Arg, Toupkhaneh, Sabzi-meidan) in their urban context around the royal citadel, aiming to answer these questions: 1-What changes in these squares over time have affected the citadel? 2-what is the role of the relationship between these squares and their spatial and functional features in other developments? Using the interpretive-historical method and primary and secondary sources as well as visual documents, the initial findings were collected, and logical reasoning of the findings, drawing diagrams, and reproduction of some maps showed that developments of Arg, Mashgh, and Sabzi-meidan squares in Naseri period (before the city expansion) and the improvement of their physical and functional condition led to the birth of squares with specific design and function in the north and south of the royal citadel; previously, these spaces were chaotic with multiple functions. Also, the changes in Arg Square and its transformation into Golshan Garden led to the birth of Toupkhaneh Square in the north of the citadel and the formation of the fourth square around this common urban context. Secondly, these four squares have been the precondition for the emergence of another: first Sabzi-meidan, then Arg, then Mashgh, and finally Toupkhaneh square were formed. On the other hand, the function and location of the squares have been in harmony with each other.