In the text, the first half of the 20th century is discussed in general, and the changes in interior architecture with the effect of currents in this process are examined within the framework of the concept of form. In this context, it is aimed to convey the formal changes in interior architecture together with the cause and effect relationship. In the historical process, various events, developments, innovations and the effects arising from them and movements emerge. Political developments and economic conditions have changed the balance of power, class differences have occurred in the social structure, and accordingly, new demands, needs, tastes and expectations have emerged in terms of architecture and interior architecture. This situation has contributed to change and transformation by feeding the currents. Considering the space and human relationship, it is observed that spaces are social products formed in the historical process. In this context, it is possible to observe the processes that the society goes through on the structures. The effects of the currents that emerged in the historical process can also be seen in architectural structures. Architectural movements have similarities as well as differences. For this reason, when examining architectural works, it is observed that there are effects of different movements, not staying in a single movement.