An electronic device includes: a first structure including a first fastening structure; a second structure disposed on an upper portion of the first structure and including a second fastening structure; a third structure disposed on an upper portion of the second structure and including a third fastening structure; and an integrated fastening structure including a first engagement portion and a second engagement portion, the integrated fastening structure being configured to directly connect the first structure, the second structure, and the third structure. Each of the first engagement portion and the second engagement portion is configured to engage a different fastening structure among the first fastening structure, the second fastening structure, and the third fastening structure.