A horn loudspeaker includes a horn housing having a top wall, an inner surrounding wall that extends downwardly from the top wall, a bottom wall that extends laterally and outwardly from the inner surrounding wall, and an outer surrounding wall that extends upwardly from the bottom wall. A cover has a top wall disposed over the top wall of the horn housing, and a surrounding wall that extends downwardly from the top wall of the cover into a gap between the inner and outer surrounding walls. Partitioning members are connected sealingly to the horn housing and the cover so as to define a plurality of sound channels thereamong. A sound-generating driver is adapted to be mounted in the horn housing for generating acoustic pressure wave which propagates through the sound channels.