The biology of the Sphecidae, even under the restricted definition, is still fairly diverse; some sceliphrines even display rudimentary forms of sociality, and some sphecines rear multiple larvae in a single large brood cell.

All are predatory and parasitoidal, but the type of prey ranges from spiders to various dictyopterans, orthopteroids and larvae of either Lepidoptera or other Hymenoptera; the vast majority practice mass provisioning, providing all the prey items prior to laying the egg.

This phylogenetic tree is based on Sann et al., 2018, which used phylogenomics to demonstrate that both the bees (Anthophila) and the Sphecidae arose from within the former Crabronidae, which is therefore paraphyletic, and which they suggested should be split into several families; the former family Heterogynaidae nests within the Bembicidae, as here defined.

Only the following subfamilies remain in the new family Sphecidae (sensu stricto) which is a monophyletic clade.

All the other digger wasp taxa that were formerly included in Sphecidae (sensu lato) were placed in the family Crabronidae, which was itself paraphyletic, and recent classifications have split Crabronidae into a number of smaller families, mostly formerly treated as subfamilies.