This list of the Mesozoic life of Idaho contains the various prehistoric life-forms whose fossilized remains have been reported from within the US state of Idaho and are between 252.17 and 66 million years of age.
Mold fossil of a shell of the Early Devonian-Late Triassic bivalve Aviculopecten †Aviculopecten – report made of unidentified related form or using admittedly obsolete nomenclature
Fossilized shell of the Silurian-Eocene articulate brachiopod Rhynchonella †Rhynchonella – report made of unidentified related form or using admittedly obsolete nomenclature
^ abLucas N. Weaver; Gregory P. Wilson; L. J. Krumenacker; Kayla Mclaughlin; Jason R. Moore; David J. Varricchio (2019). "New multituberculate mammals from the mid-Cretaceous (lower Cenomanian) Wayan Formation of southeastern Idaho and implications for the early evolution of Cimolodonta". Journal of Vertebrate Paleontology. 39 (2): e1604532. doi:10.1080/02724634.2019.1604532. S2CID196655261.