A polyester resin composition comprises (A) about 100 parts by weight of polyester resin with a melting point greater than about 200° C. and including repeat units of Formula 1; (B) about 0.1 to about 80 parts by weight of white pigment; and (C) about 0.01 to about 80 parts by weight of filler. The polyester resin composition of the present invention does not exhibit deteriorated reflectance and impact strength and also has good heat resistance, non-yellowing property and humidity resistance and can be used in a light emitting diode (LED) reflector.