Plate tectonics models proposed for the Ouachita foldbelt include cordilleran models, flip models, and collision models. Upper-plate cordilleran models and flip models fail because (1) no Paleozoic plutonic rocks or high-temperature, low-pressure metamorphic rocks have been found, (2) volcanic and metamorphic components are rare in the Carboniferous Ouachita flysch, and (3) the subsidence history of the craton suggests an Atlantic-type margin during part of the Carboniferous flysch interval. Collision models fit the known geologic data best. An oceanic part of the North American plate was consumed beneath a southern continental mass (South America?), which contained the magmatic arc. Collision began in Early Pennsylvanian time, with postcollision convergence through earliest Permian time.