The possibilities and restrictions of the tunnel formwork technology which has been often used in the last two decades in Türkiye, has to be known thoroughly in order to design and produce better projects. This is the reason why, firstly the tunnel formworks are described. The elements constituting the tunnel formworks, the dimensions and the way they get together to form spaces are explained in this paper Later the possibilities and restrictions of the tunnel formworks bring w the design are put out with the help of examples from real projects and drawings. The standard limiting spatial dimensions and forms of tunnel formworks and the restrictions caused by the dismantling and the carriage of the tunnel formwork are described according to examples and the results are summarized in a table at the end of the paper.