The Mozarabs (from Arabic: مُسْتَعْرَب, romanized: musta‘rab, lit. 'Arabized'), or more precisely Andalusi Christians, were the Christians of al-Andalus, or the territories of Iberia under Muslim rule from 711 to 1492. Following the Umayyad conquest of the Visigothic Kingdom in Hispania, the Christian population of much of Iberia came under Muslim control.

Initially, the vast majority of Mozarabs kept Christianity and their dialects descended from Latin. Gradually, the population converted to Islam—an estimated 50% by the year 951—and was influenced, in varying degrees, by Arab customs and knowledge, and sometimes acquired greater social status in doing so. The local Romance vernaculars, with an important contribution of Arabic and spoken by Christians and Muslims alike, are referred to as Andalusi Romance (also called Mozarabic language). Mozarabs were mostly Catholics of the Visigothic or Mozarabic Rite. Due to Sharia and fiqh being confessional and only applying to Muslims, the Christians paid the jizya tax, the only relevant Islamic law obligation, and kept Roman-derived, Visigothic-influenced civil law.

Most of the Mozarabs were descendants of local Christians and were primarily speakers of Romance varieties under Islamic rule. They also included those members of the former Visigothic ruling elite who did not convert to Islam or emigrate northwards after the Muslim conquest. Spanish Christians initially portrayed Muslims primarily as military or political enemies, but with time, Islam came to be seen as a religion and not merely a threat. Spanish Christians sought to discourage apostasy from Christianity and to defend Christian beliefs, but they increasingly became connected to the dar al-Islam (land of Islam), through shared culture, language, and regular interaction.

A few were Arab and Berber Christians coupled with Muslim converts to Christianity who, as Arabic speakers, felt at home among the original Mozarabs. A prominent example of a Muslim who became a Mozarab by embracing Christianity is the Andalusi rebel and anti-Umayyad military leader, Umar ibn Hafsun. The Mozarabs of Muslim origin were descendants of those Muslims who converted to Christianity following the conquest of Toledo, and perhaps also following the expeditions of King Alfonso I of Aragon. These Mozarabs of Muslim origin who converted en masse at the end of the 11th century, many of them Muladí (ethnic Iberians previously converted to Islam), are distinct from the Mudéjars and Moriscos who converted gradually to Christianity between the 12th and 17th centuries.

Separate Mozarab enclaves were located in the large Muslim cities, especially Toledo, Córdoba, Zaragoza, and Seville.

Mozarab (Spanish: mozárabes [moˈθaɾaβes]; Portuguese: moçárabes [muˈsaɾɐβɨʃ]; Catalan: mossàrabs [muˈsaɾəps]; from Arabic: مُسْتَعْرَب, romanized: musta‘rab, lit. 'Arabized') is first documented in Christian sources from the 11th century; the term Mozarab was not used by Muslims to describe Christians. Contemporary Arabic sources described Christians as naṣārā (نصارى 'Nazarenes'), or imprecisely by their legal-religious status: ahl adh-dhimma (أهل الذمة 'people of the covenant') or mu‘āhidūn (معاهدون 'contractual partners').

The term Mozarab, now sometimes applied broadly to all Christians in al-Andalus, is imprecise; many Christians living in Islamic Spain resisted Arabization, for example.

Christians and Jews were designated as dhimmi under Sharia (Islamic law). Dhimmi were allowed to live within Muslim society, but were legally required to pay the jizya, a personal tax, and abide with a number of religious, social, and economic restrictions that came with their status. Despite their restrictions, the dhimmi were fully protected by the Muslim rulers and did not have to fight in case of war, because they paid the jizya.