A white thermosetting silicone resin composition for molding an optical semiconductor case and a case for an optical semiconductor such as LED are provided. The composition comprises (A) a thermosetting organopolysiloxane, (B) a white pigment, (C) an inorganic filler (excluding the white pigment), (D) a condensation catalyst, and (E) a coupling agent represented by the following formula: R3dSi(OR2)e wherein R3 represents an organic group containing a mercapto group, a glycidyl group, or an amino group, R2 represents a C1-4 organic group, d represents 1 or 2, and e represents 2 or 3; wherein content of the white pigment (B) is 1 to 50% by weight in the entire composition, and total content of the white pigment (B) and the inorganic filler (C) is 70 to 93% by weight in the entire composition. When cured, it has excellent whiteness, consistency, and resistance to heat, light, yellowing, and warping.