Gallic horse (Equus caballus gallicus) is a prehistoric subspecies of Equus caballus (the horse) that lived in the Upper Paleolithic. It first appeared in the Aurignacian period because of climatic changes and roamed the territory of present-day France during the Gravettian and up to the end of the Solutrean. Its fossils, dated from 40,000 to around 15,000 years BC, are close to those of Equus caballus germanicus (the Germanic horse) and may not correspond to a valid subspecies. First described by François Prat in 1968, it is around 1.40 m (4.6 ft) tall and differs from Equus caballus germanicus mainly in its dentition and slightly smaller size.

There is no consensus among specialists as to the validity of the subspecies Equus caballus gallicus. Based on paleontological discoveries at numerous sites in present-day France, such as Solutré, Camiac and La Quina, François Prat postulates that Equus caballus gallicus gradually replaced Equus caballus germanicus and that the two subspecies are distinct. On the other hand, Véra Eisenmann, a CNRS and MNHN researcher, postulates that the specimens attributed to Equus caballus gallicus do not present a sufficiently distinct variation from the subspecies Equus caballus germanicus. However, it is accepted that Equus caballus arcelini, a well-differentiated subspecies, has replaced the populations made up of specimens traditionally attributed to Equus caballus germanicus and Equus caballus gallicus.

The discovery of this subspecies followed the examination of horse bones found at Solutré and recovered by Jean Combier. Noting differences in morphology associated with different dating (suggesting different species or subspecies among these fossils), François Prat and Combier postulated the existence of two differentiated types of horse on this site: Equus caballus gallicus and Equus caballus arcelini. The name chosen refers to the territory that Equus caballus gallicus occupied, Gaul. Because it forms most of the fossils found at Solutré, Equus caballus gallicus is generally referred to by the still-common name of "Solutré horse". It is considered a subspecies. As the evolutionary history of Equidae remains controversial, it is sometimes (rarely) considered a species of the genus Equus, named Equus gallicus.

Not all prehistorians and paleontologists recognize the existence of this taxon. Vera Eisenmann postulates that Equus caballus germanicus can show variations in size and dentition, and therefore that Equus caballus gallicus never existed. According to her, Equus caballus arcelini would have succeeded Equus caballus germanicus directly 15,000 years BC, with much more visible morphological changes.

According to a theory put forward by N. Spassov and N. Iliev in 1997, it would seem that "cut off from the parent population in northern and central Europe by climatic barriers, Equus (caballus) germanicus evolved into gallicus and then arcelini in western Europe", while horses in eastern and southeastern Europe evolved differently. According to Vera Eisenmann, the transition from Equus caballus germanicus to gallicus appears to have been gradual, accompanying changes in the biotope. As horses eat more and more grasses, their dentition changes.

Equus caballus gallicus was first described by François Prat in 1968. Smaller than Equus caballus germanicus (1.40 m or 4.6 ft on average), it has a different morphology, with more pronounced caballins characters on its dentition. It is also lighter than the latter, with broad hooves and a short, voluminous head with strong teeth, resting on a short, broad neck. Based on cave paintings and primitive horses such as the Przewalski, specialists attribute a dun or pangaré coat (light brownish-yellow, black manes and tips, discoloration of the underside).

Equus caballus gallicus appeared after the first half of Würm III. It is inseparable from the Aurignacian and Gravettian periods. It lasted until the Solutrean and Magdalenian periods. Between 35,000 and 22,000 B.P., the climate in present-day France was cold or temperate. At this time, there were vast areas of grassland, ideal for herding horses. It is then possible that a new species or subspecies better adapted to climatic constraints succeeded Equus caballus gallicus in south-western France at the end of the Würm IV, but this question remains debated.

Equus caballus gallicus preferred to live in "dry to compound steppe environments" with few hygrophilous plants, in cold, dry climates, where grass was abundant. Gregarious, it congregated in large herds and preferred large, open areas, enabling it to move quickly in search of meadows where it could feed. It tolerated wide temperature ranges, as well as temperate climates.