Naphrys pulex is a species of spider from the family Salticidae that is native to Canada and the United States.
The species was first described as Attus pulex by Nicholas Marcellus Hentz in 1846. It was later placed in a number of other genera, including Habrocestum, until a review of that genus in 1981 placed it in Naphrys.
Males have a total length of around of which the carapace makes up about . The fourth leg is longest, followed by the third, first and second. The general coloration is described as "cryptic". There is a yellowish bar-shaped mark on the abdomen. The legs have spots and rings. Females are longer than males, with a total length of , with a carapace long. Females have a similar coloration to males, but less distinct. The larger size and the shape of the male palpal bulb distinguish this species from others, such as Naphrys acerba.
Naphrys pulex is native to Canada and the United States, where it is found mainly in the east. It has been observed on walls, grass and litter, on the ground, and on tree trunks.
Naphrys pulex feeds mainly on ants.