A sand-removing seat belt buckle has a housing and a latching assembly. The housing has a chamber, a first opening and a second opening formed through two ends of the housing, at least one sand cavity formed through a bottom of the housing and being adjacent to the second opening, and at least one support bump formed on an inner bottom of the housing. The latching assembly serves to latch and unlatch an insertion member, and is securely mounted in the housing and on top of the at least one support bump, so that a space is formed between the insertion member and the inner bottom of the housing and communicates with the first opening, the second opening and the sand cavity. Sand, mud and crushed pebbles entering from the first opening can be removed from the sand cavity and the second opening through the space without being deposited inside the seat belt buckle.