According to various embodiments, an electronic device may include a first housing, a second housing foldably connected to the first housing through a hinge device, and a flexible display including a first portion facing the first housing, a second portion facing the second housing, and a bendable third portion connecting the first portion and the second portion and facing the hinge device. The flexible display may include a window layer including a first region facing the first portion, a second region facing the second portion, and a third region facing the third portion and configured to be bendable, a display panel disposed under the window layer, and a subsidiary material layer disposed under the display panel. The window layer may include a glass layer including a plurality of first openings formed at specified intervals and a filling member filled in the plurality of first openings. Other embodiments may be possible.