Duplo is made by the LEGO company, developed in the late '60s. Duplo is more geared toward preschoolers. They have a tendency to be larger and width and length. Their divets are a little larger and more open than regular LEGO block, thereby making them more easily interlocking. They can be compatible with regular LEGOs, too, when it come to interlocking them. Duplos tend to come in a limited range of colors--red, yellow, blue, white--and are typically building sets like the train set we reviewed.