A display device includes first and second substrates, and first and second alignment keys. The first and second substrates have first and second display regions and first and second peripheral regions, respectively. The first alignment key is disposed in the first peripheral region of the first substrate. The first alignment key includes a first pattern and a second pattern. The second alignment key is disposed in the second peripheral region of the second substrate such that the second alignment key faces the first alignment key. As a result, first alignment key may be formed through a procedure of forming the pixel electrode. Therefore, there exists no deviation between the first alignment key and the pixel electrode and the first alignment key may be easily detected because of the first pattern that is opaque, so that misalignment is prevented.