A new distinct cultivar of Osteospermum plant named 'Sunny Amanda', characterized by ray florets with the following mixture of colors: upper surface (when opening): RHS 157D, with a slight yellow tinge at base, gradually changing to RHS 163B at the apex, white to gray-orange; underside (when opening): RHS 162D at base, gradually changing to RHS 161A at the apex with 4 stripes of RHS 177A, gray-orange, (under some light conditions the underside appears golden); upper surfaces (fully opened): RHS 157D, with a slight yellow tinge at base and almost half-way up ray floret, then gradually changing to RHS 163B at the apex, white to gray-orange; underside (fully opened): RHS 162D at base, gradually changing to RHS 161A at the apex with 4 stripes of RHS 153A; disk florets with the following mixture of colors: upper surfaces(when opening): RHS N187D, gray purple; underside (when opening): RHS N155D, white; upper surfaces (fully opened); petal tips are RHS N187, purple; underside (fully opened): RHS N155D, white; dense and bushy plant form; with globular plant habit; moderately vigorous growth habit, but less need for chemical growth retardation, and obovate to lanceolate leaves.