Norman (2002) coined a stem-based definition for this taxon. It is a junior synonym of the stem-based taxon Styracosterna (Sereno 1998), as both definitions use Camptosaurus as an external specifier and a hadrosaurid as an internal specifier (note than Norman 2002:fig. 35 positioned Iguanodontoidea at a less inclusive node than his definition calls for). Sereno (1986) was first to use Iguanodontoidea (Hay 1902) on a cladogram, considering the taxon a Hyperfamily in his ranked classification, one that included a subordinate superfamily (Hadrosauroidea). Later Sereno (1997) coined Hadrosauriformes as a replacement name for Iguanodontoidea, because of potential confusion arising from the superfamilial ending -oidea for a taxon that circumscribes another with the same suffix.
Hay (1902) was first to use the superfamilial form of Cope's family group (Iguanodontoidea), which he later modified to Iguanodontoidae (Hay 1930), here considered a spelling variant.