A thin film deposition apparatus includes: a chamber; a mask stage in the chamber and configured to support a mask; a jig in the chamber and above the mask stage, the jig being configured to move in a direction of the mask stage; and a rail in the chamber and configured to support the movement of the jig. Another thin film deposition apparatus includes a chamber, a mask stage positioned within the chamber and configured to support a mask, a camera part proximate to a side of the mask stage, and a jig above the mask stage and configured to move in a direction of the mask stage and over the camera part. The jig is further configured to radiate laser beams in a downward direction from the jig to obtain first scanning data regarding the mask stage and second scanning data regarding the camera part.