Presented herein is an illuminated keyboard having: a key module having a plurality of keycaps, scissors structures, elastic members, and a membrane circuit board; a keyboard base plate having a plurality of positioning members corresponding to the keycaps and integrally formed on the keyboard base plate for positioning the keyboard module on the keyboard base plate; a light guiding plate disposed beneath the key module and over the keyboard base plate, the light guiding plate having a light incoming surface, a bottom surface intersecting the light incoming surface, a light outgoing surface opposite to the light incoming surface, and provided with light holes corresponding to the positioning members; light sources arranged on one side of the light incoming surface of the light guiding plate, wherein a light emitted from the light sources is transmitted into the light guiding plate from the light incoming surface and transmitted out of the light guiding plate from the outgoing surface; and a reflecting sheet disposed beneath the bottom surface of the light guiding plate for reflecting the light emitted from the light sources into the light guiding plate, the reflecting sheet having through holes corresponding to the positioning members and the light holes.