The snap-in-place building block has two internal support brackets constructed from durable plastic that are equipped with male and female interlocking devices, a rebar clip, a furring strip, and exterior flanges that are molded into a block body made from foamed plastic. A body of foamed plastic is molded around the brackets, the body defining two hollow cores, one bracket being disposed in each of the cores. A horizontal channel is formed between adjacent blocks when stacked above each other. The cores and horizontal channels receive concrete or mortar that forms vertical columns and horizontal beams within the wall. An exterior veneer is attached to the protruding exterior flanges on one side of the building block. The configuration of the block may be altered to allow for half-blocks and corner blocks.