A wideband slot-loading loudspeaker includes a speaker driver configured to reproduce sound; an enclosure in which the speaker driver is disposed; a reflective member spaced apart from a front surface of the speaker driver, wherein a slot is formed in a space between the speaker driver and the reflective member; an acoustic discharge port provided at one end of the slot, the acoustic discharge port configured to discharge the sound reproduced by the speaker driver; at least one opening provided in the reflective member; and a sound resistance member disposed at the at least one opening.