A loading determination system includes: a storage unit configured to store dimension information for each of a plurality of loading regions which is present in a vehicle, the dimension information being relevant to an upper limit of a dimension of a parcel which is able to be loaded in each of the loading regions; and a control unit configured to determine, based on the dimension information, whether a first parcel which is planned to be loaded is able to be loaded in the vehicle and output a determination result of whether the first parcel is able to be loaded, and first information relevant to a first loading region in which the first parcel is planned to be loaded when the first parcel is able to be loaded, the first loading region being included in the plurality of loading regions.