A method of manufacturing a deposition mask is disclosed. In one aspect, the method includes depositing a first photoresist layer on a substrate, aligning a first photomask over the first photoresist layer and developing the first photoresist layer to form a plurality of first photoresist patterns having sides that gradually narrow toward the substrate. The method also includes forming a metal layer over the first photoresist patterns and a portion of the substrate exposed by the first photoresist patterns, depositing a second photoresist layer over the metal layer and aligning a second photomask over the second photoresist layer and developing the second photoresist layer to form a plurality of second photoresist patterns between the first photoresist patterns. The method further includes etching the metal layer to form a pattern hole, removing the first and second photoresist patterns and separating the substrate so as to form a deposition mask.