The Archer City Formation is a geological formation in north-central Texas, preserving fossils from the Asselian and early Sakmarian stages of the Permian period. It is the earliest component of the Texas red beds, introducing a tropical ecosystem which will persist in the area through the rest of the Early Permian. The Archer City Formation is preceded by the cool Carboniferous swamp sediments of the Markley Formation, and succeeded by the equally fossiliferous red beds of the Nocona Formation. The Archer City Formation was not named as a unique geological unit until the late 1980s. Older studies generally labelled its outcrops as the Moran or Putnam formations, which are age-equivalent marine units to the southwest.

The sediments of the Archer City Formation reconstruct a coastal floodplain crossed by small meandering rivers and isolated ponds. The climate was hot and monsoonal, preserving a variety of paleosols and plant assemblages ranging from dry upland forests to moist riverside galleries. "Seed ferns" (Sphenopteris, Autunia, Odontopteris, etc.) and early conifers (Walchia, etc.) occupied drier soils, while marattialean ferns (Pecopteris, Asterotheca, etc.) and horsetails (Sphenophyllum, Annularia, Calamites, etc.) were prominent in more humid areas.

The Archer City Formation preserves a diverse fauna of fossil vertebrates in pond bonebeds across Archer and Clay counties. Many fossils are rare fragments of species which are better-preserved in younger parts of the red beds. Nevertheless, complete skeletons and important type specimens are also known from the formation. Some notable synapsids include Apsisaurus witteri, Edaphosaurus boanerges, Ophiacodon uniformis, and Dimetrodon milleri. Early reptiles such as Protorothyris archeri and Romeria spp. make up a small component of the terrestrial fauna. Amphibians are common in every niche, with examples such as Phonerpeton pricei, Neldasaurus wrightei, Edops craigi, Eryops megacephalus, and Pantylus cordatus, just to name a few. The rivers were roamed by Orthacanthus texensis (a xenacanth "shark") and Ectosteorhachis nitidus (a megalichthyid fish).

Fossil bonebeds in the vicinity of Archer City were first investigated in detail by Alfred Romer and Llewellyn Price, starting in the late 1920s. At the time, these bonebeds were assigned to the Pueblo, Moran, or Putnam formations of the Cisco Group. The Archer City Formation was first named in a 1987 geological map seeking to update the stratigraphy of North Texas. The formation and its stratigraphic placement were formalized in text a year later.

The formation outcrops in an arc from Montague County in the east, through Clay, Archer, and Young counties, as far as Throckmorton County in the west. It is most broadly exposed in Clay and Archer counties, including under its namesake of Archer City.

The Archer City Formation is a unit of the Bowie Group, lying above the Markley Formation and below the Nocona Formation of the Wichita Group. Some publications have labelled the Nocona Formation as the "Upper Archer City Formation", thus considering the Archer City Formation to be a unit of the Wichita Group. This proposal is not widely agreed upon. The Cisco Group and its constituent formations have been restricted to marine strata further south and west. Of these strata, the Archer City Formation is roughly equivalent in time to the uppermost Pueblo Formation, the Moran Formation, the Sedwick Formation, and the Santa Anna Branch shale (= Putnam Formation), from oldest to youngest.

Based on correlations with coastal strata further west, the Carboniferous-Permian boundary is positioned near the top of the Markley Formation. This suggests that the Archer City Formation occupies most of the Asselian (299–293 Ma), the first global stage of the Permian Period. The plant fossils of the Archer City Formation also resemble those of Asselian Europe. The upper part of the Archer City Formation may extend into the succeeding Sakmarian stage (293–290 Ma). The Santa Anna Branch Shale and overlying Coleman Junction Limestone both preserve fossils of Sweetognathus merrilli, a conodont index fossil of the early Sakmarian. The Asselian and Sakmarian global stages are equivalent to the early-middle parts of the Wolfcampian regional stage.

As with the rest of the Texas red beds, the Archer City Formation was deposited on a coastal plain between an inland marine basin in the west and patches of steadily eroding mountains in the north and east. Some of the mountains are still standing in the present day, such as the Wichita Mountains and Arbuckle Mountains, while others have been fully eroded or buried, such as the Texan portion of the Ouachita Mountains. The marine basin is formally known as the Midland Basin, a major component of the Permian Basin oil field. Rising sea levels through the Early Permian allowed the coastline to gradually transgress northward and eastward. The major bonebed sites of the Archer City Formation were probably 40–60 km (25–37 mi) away from the coast.