A mask for thin film deposition of a display apparatus having both end portions coupleable to a frame in a state of tension in a lengthwise direction thereof, the mask including: a first portion having a first thickness and a plurality of pattern holes through which a deposition material may pass; a second portion comprising a welding portion having a second thickness configured to be coupled to a frame; and a third portion connecting the first portion and the third portion, wherein the first thickness is less than the second thickness, and the third portion includes an inclined surface connecting the first portion and the second portion.