The results of an extensive investigation of larval morphology of Dermestidae (skin, larder, and carpet beetles) are presented and illustrated with over 150 original illustrations. The gastric caeca in Dermestes L., the structure of mandible base in Thylodriini Beal and Trinodini Beal, and the number of Malpighian tubules and abdominal nervous ganglia in various species of Dermestidae are reported for the first time. The first descriptions of the larvae of Cryptorhopalum triste LeConte, Anthrenocerus stigmacrophilus Armstrong, and Myrmeanthrenus frontalis Armstrong are presented. A parsimony analysis based on larval morphological data indicates the monophyly of Dermestidae exclusive of Orphilus Erichson. The phylogenetic position of Orphilus remains ambiguous. A provisional classification of Dermestidae based on larval data is proposed. The character evolution, the fossil record, and the distribution of extant Dermestidae are discussed in light of phylogeny.