While a basal ornithischian position outside Ornithopoda was retained by Paul Sereno in 1991, it was considered a possibly valid taxon based on its prominent anterior and posteriormost denticles. Galton revised his classification of the taxon in 1994, considering it only referrable to Ornithopoda, and not closely related to Echinodon. Trimucrodon was then compared favourable by Galton in 1996 to the also Portuguese taxon Taveirosaurus, previously considered a pachycephalosaur.
While Paul Sereno proposed a basal ornithischian position outside Ornithopoda in 1991, it was considered a potentially valid taxon based on its prominent anterior and posterior denticles.  Galton revised his classification of the taxon in 1994, considering it only referrable to Ornithopoda, and not closely related to Echinodon. Trimucrodon was then compared favorably by Galton in 1996 to the also Portuguese taxon Taveirosaurus, previously considered a pachycephalosaur.