The history of the region comprising present-day Morocco has been shaped by the interaction of the original Berber population and the various foreign peoples who successively invaded the country. The first of the foreign invaders well known to history were the Phoenicians, who in the 12th century bc established trading posts on the Mediterranean coast of the region. These colonies were later taken over and extended by the Carthaginians. The conquest of Carthage by Rome, in the 2nd century bc, led to Roman dominance of the Mediterranean coast of Africa. About ad 42 the northern portion of what is now Morocco was incorporated into the Roman Empire as the province of Mauretania Tingitana. In the Germanic invasions that attended the decline of the Roman Empire, the Vandals in 429 occupied Mauretania Tingitana. The Byzantine general Belisarius defeated the Vandals in 533 and established Byzantine rule in parts of the country.

In the late 7th century the Muslim invasion from the east reached Morocco. In 740 the Berbers revolted against the rule of the Umayyads of Damascus, and the Berbers remained independent of Umayyad and Abbasid rule. After some three centuries of local wars of conquest and shifting control, a Berber confederation known as the Almoravids conquered all of Morocco in the middle of the 11th century and enforced their rule over the Muslim areas of Spain as well. In the early 12th century another Berber clan, the Almohads, revolted against the Almoravid dynasty and became the rulers of Morocco and all Muslim Spain. They were gradually driven from Spain in the 13th century and were defeated in Morocco in 1269 by the Marinids. Under the Marinids' rule, which lasted to the mid-15th century, Muslim mysticism, or Sufism, developed in Morocco. After the fall of the Marinids the country was divided into small independent states until the Sa'dis established their rule over Morocco for a century after about 1550.

During 1974 and 1975 Morocco exerted much pressure on Spain to relinquish Spanish Sahara. When the Spanish left in 1976, they ceded the northern two-thirds of the colony to Morocco, while Mauritania received the southern third. This disposal of the phosphate-rich territory was disputed by the Polisario Front, a Saharan nationalist guerrilla movement, which proclaimed Western Sahara an independent nation, called the Sahrawi Arab Democratic Republic (SADR). Although burdened by the ensuing guerrilla warfare, Morocco resolved to continue the fight alone after Mauritania decided to withdraw from the conflict in 1979. Faced with mounting international opposition, King Hassan nevertheless committed additional troops and resources to the effort to protect the phosphate mines and major towns from Polisario harassment. In 1984 Morocco quit the Organization of African Unity (OAU) to protest its seating of a Polisario delegation. Efforts by the United Nations (UN) to mediate the dispute continued throughout the 1980s and 1990s. A cease-fire was implemented in Western Sahara in 1991, and a UN-sponsored referendum on self-determination was postponed repeatedly due to disagreements over voter eligibility. In the early and mid-1990s Morocco was criticized by the Polisario Front for encouraging Moroccans to migrate to Western Sahara in hopes of having them counted as eligible voters.