Stenoterommata crassistyla is a species of mygalomorph spiders of Argentina, named after its wide embolus (stylus) in males, distinguishing this species from the sympatric S.

Females are distinguished from other Stenoterommata having multireceptaculate spermathecae by the presence of inferior tarsal claws on the anterior legs.

Males have the palpal tibia with a basal notch at either side of the base, and swollen.

The species is distinguished from S. tenuistyla by lacking the short spines on the male metatarsus I, characteristic of said species.

Uruguay and Argentina Entre Ríos and northern Buenos Aires Province.