The nematode order Oxyurida is unique in including species for which definitive host ranges are broad and may include vertebrate or invertebrate hosts. The superfamily Thelastomatoidea is a highly diverse assemblage of oxyurids occurring in cockroaches, diplopods, hydrophilid beetles, passalid beetles, several other coleopteran larvae, mole crickets, and, with few representative species documented, other arthropod hosts. Published research and revision of the Thelastomatoidea, particularly in the 1980s and 1990s, provided several interesting hypotheses on the systematics and evolution of this group. In this review, these hypotheses are examined in the context of recent advances in taxonomy, discovery of additional species diversity and distribution, and preliminary phylogenetic hypotheses that have been proposed. There continues to remain a paucity of phylogenetic data that explore the phylogenetic relationships of the Thelastomatoidea and their relationships to vertebrate-parasitizing pinworms. A combination of mitochondrial and nuclear DNA sequences for representative species across all of the major lineages will be important for more robust phylogenetic hypotheses. Much broader geographical and host taxon sampling is necessary to determine true diversity of the Thelastomatoidea. Modern approaches to species descriptions, such as improvements in light and scanning electron microscopy and the use of molecular approaches to matching male and female nematodes, can also be applied to improve our understanding of the evolution of these fascinating parasites.