A thermosetting silicone resin composition for an LED reflector has: a thermosetting resin; at least one kind of white pigment selected from titanium oxide, zinc oxide, zirconium oxide, magnesium oxide, barium carbonate, magnesium silicate, zinc sulfate, and barium sulfate; and an inorganic filler other than the pigment, which contains at least one kind of inorganic filler that has an average particle diameter of 30 μm to 100 μm and a refraction index that is different from a refraction index of a cured material of the thermosetting resin by 0.05 or more, and at least one kind of inorganic filler that has an average particle diameter of less than 30 μm. The thermosetting resin composition provides a cured material that has excellent heat and light resisting properties and hardly leaks light, a reflector for an LED obtained by molding using the composition, and an optical semiconductor apparatus using the reflector.