A polishing slurry is disclosed which includes about 0.01 wt % to about 10 wt % of polishing particles, about 0.005 wt % to about 0.1 wt % of a dispersing agent, about 0.001 wt % to about 1 wt % of an oxide-polishing promoter including a pyridine compound, about 0.05 wt % to about 0.1 wt % of a nitride-polishing inhibitor including an amino acid or an anionic organic acid, and water. A method for manufacturing a display device including an active pattern disposed on a base substrate, a gate metal pattern including a gate electrode overlapping the active pattern, a planarized insulation layer disposed on the gate metal pattern, and a source metal pattern disposed on the planarized insulation layer is also disclosed.