A keypad assembly for a portable terminal is disclosed. The keypad assembly for the portable terminal includes a light guide plate which has reflection patterns locally formed on a lower surface of the light guide plate for reflecting a part of light transmitted in the light guide plate toward an upper surface of the light guide plate. The keypad assembly also includes at least one key button seated on the light guide plate, for outputting the light reflected by the reflection patterns out of the keypad assembly, upper and lower cases for containing the light guide plate, a switch substrate seated on a bottom surface of the lower case and having at least one switch, and an extension member which extends from an upper case of the portable terminal toward the switch substrate. The extension member has a reflection filter for reflecting the light exiting from the light guide plate toward the light guide plate back. The reflection filter is formed on an inner surface facing a side surface of the light guide plate.