The Ark-La-Tex (a portmanteau of Arkansas, Louisiana, and Texas; also stylized as Arklatex or ArkLaTex) is a socio-economic region where the Southern U.S. states of Arkansas, Oklahoma, Louisiana, and Texas join together. The region contains portions of Northwest Louisiana, Northeast Texas, and South Arkansas as well as Oklahoma's southeasternmost county, McCurtain County (part of Choctaw Country).

The population of the 40-county core region as of 2020 is 1,469,860 people, down from 1,515,056 in 2010. Shreveport, Louisiana, with 187,593 people in 2020, is the largest city, economic and geographic center of the region, and principal hub for both the Shreveport–Bossier City metropolitan area and Northwestern Louisiana. Longview, Texas, with a population of 81,683 people in 2020, is the second-largest city as well as a principal city of the Tyler–Longview metropolitan conurbation and Greater Longview metropolitan area. The twin cities of Texarkana, Texas, and Texarkana, Arkansas, are the fourth- and sixth-largest cities, respectively, but collectively make up the region's third-largest metropolitan area (with a combined population exceeding 140,000 residents) as the center of the Texarkana metropolitan area encompassing Miller County, Arkansas, and Bowie County, Texas. Other cities in the Ark-La-Tex with 20,000 or more residents include Bossier City, Louisiana; Nacogdoches, Texas; Marshall, Texas; and Ruston, Louisiana.

The counties in the area's western section are largely part of the East Texas region (except for McCurtain County, Oklahoma, which is part of the Choctaw Country tourist region) and mainly encompass the Tyler–Longview–Lufkin–Nacogdoches television market area, while the counties and parishes in the eastern half of the region are included in the Shreveport–Texarkana television market. However, some Arkansas counties—under certain, looser definitions of the Ark-La-Tex region—in northwesternmost areas of the southwestern section of the state are included in the Little Rock viewing area.

Although use of the term to refer to the tri-state region dates back to the early 1900s, the name "Ark-La-Tex" was popularized regionally by a Shreveport Chamber of Commerce promotional campaign developed in 1932–33 to increase tourism in the area.

The campaign, dubbing the area as "The Land of Arklatex", was based on the idea that "the interests of all the people in the Tri-state area of South Arkansas, North Louisiana and East Texas are practically identical in matters pertaining to agriculture, industry, commerce and trade, and education." The region is alternatively, although seldom in most media and promotional parlance, referred to as "Arklatexoma", which more inclusively encompasses McCurtain County and other parts of extreme Southeastern Oklahoma that lie along the Red River.

The Ark-La-Tex covers over 14,000 square miles (36,000 km²) across the four-state area; if the Ark-La-Tex were a U.S. state, it would be larger than Maryland. Most of the Ark-La-Tex is located in the Piney Woods, an ecoregion of dense forests of mixed deciduous and conifer flora. The forests are periodically punctuated by sloughs and bayous that are linked to larger bodies of water such as Caddo Lake or the Red River. Three of the four National Forests located within the Piney Woods of East Texas are wholly or partially within the Ark-La-Tex boundaries: Angelina National Forest (spanning Angelina, Nacogdoches, San Augustine and Jasper counties), Sabine National Forest (near Hemphill) and Davy Crockett National Forest (between Lufkin and Crockett).

The Red River is the principal mainstem waterway in the region, exiting from the eastern end of Lake Texoma and running generally east along the Oklahoma–Texas border towards Southwestern Arkansas (entering it near the state line between Little River County, Arkansas, and Bowie County, Texas) before turning southward northwest of Texarkana (in so doing, forming the eastern border of Miller County) and passing into Northwestern Louisiana. The bordering Louisiana cities of Shreveport and Bossier City were developed along the river bank; its span within the Ark-La-Tex ends in Natchitoches Parish, Louisiana (where the Red River spans to the adjacent northwest of the parish's namesake county seat), at its intersection with Grant and Rapides parishes.

As with all vernacular regions, the Ark-La-Tex has no official boundaries or status and is defined differently by various sources. Most definitions of the Ark-La-Tex delineate the region as encompassing 40 parishes and counties, and most weather radars suggest a 40-county or -parish area.