A thin film transistor (“TFT”) array panel is provided. The TFT array panel includes an insulation substrate, a gate line formed on the insulation substrate and including a gate electrode, a data line insulated from and intersecting the gate line, and including a source electrode, a drain electrode opposite to the source electrode on the gate line, and a semiconductor formed in a layer between the data line and the gate line, and having a protruding portion extending below the drain electrode, wherein a portion of the semiconductor extending towards the drain electrode, from an area occupied by the data line, is positioned within an occupying area of the gate line including the gate electrode.