Atlas Mountains, mountain system in northwestern Africa, consisting of several distinct ranges, extending between Tunisia and Morocco, a distance of 2,200 km (1,400 mi). The Atlas Mountains are an extension of the Alpine system of Europe. The highest range, called the High, or Grand, Atlas, is in southwestern Morocco. Toubkal, with an elevation of 4,165 m (13,665 ft), is the highest known peak in this range. Lying to the north, in central Morocco, is the next highest range, the Middle Atlas, with a maximum elevation of about 3,000 m (11,000 ft). Other prominent ranges of the system include the Anti-Atlas (maximum elevation, about 2,100 m/6,800 ft), south of and parallel to the High Atlas; the Saharan Atlas, extending from eastern Morocco into Algeria, with a maximum elevation of 2,328 m (7,638 ft) at Jebel Chelia; and the Tell, or Maritime, Atlas averaging 1,500 m (5,000 ft) in elevation and extending along the coast of the Mediterranean Sea from a point near the eastern end of the Strait of Gibraltar to Cape Bon, in Tunisia. Jebel Sidi Moussa (ancient Abila or Abyla), a promontory (846 m/2,775 ft) marking the western extremity of the Little Atlas, and the Rock of Gibraltar, on the European side of the strait, are called the Pillars of Hercules.

The Atlas system is traversed by numerous passes that provide routes between the coast and the Sahara. The northern slopes of the High Atlas and the northern and southern slopes of the Middle Atlas are densely forested; cedar, pine, cork, and oak are the predominant species of trees. Fertile valleys and extensive tracts of pasturage lie in these ranges and other sections of the system. The ranges contain a wide variety of mineral deposits, including gold, silver, lead, zinc, iron, manganese, antimony, phosphates, and petroleum, but these resources are only slightly exploited.

The Atlas Mountains are the traditional territory of the Berbers, who were driven inland to the mountains by the Arabs in the 7th century ad. Sections of the system, chiefly in the coastal areas, were known to the Europeans of antiquity, but not until the second half of the 19th century did systematic exploration of the various ranges begin.