The Crabronidae are a large paraphyletic group of wasps, including nearly all of the species formerly comprising the now-defunct superfamily Sphecoidea. It collectively includes well over 200 genera, containing well over 9000 species. Crabronids were originally a part of the Sphecidae, but the latter name is now restricted to a separate family based on what was once the subfamily Sphecinae. Several of the subfamilies of the Crabronidae are often treated as families in their own right, as is true of the most recent phylogenies.

A wasp is any insect of the narrow-waisted suborder Apocrita of the order Hymenoptera which is neither a bee nor an ant; this excludes the broad-waisted sawflies (Symphyta), which look somewhat like wasps, but are in a separate suborder. The wasps do not constitute a clade, a complete natural group with a single ancestor, as bees and ants are deeply nested within the wasps, having evolved from wasp ancestors. Wasps that are members of the clade Aculeata can sting their prey.