Aljamiado (Spanish: [alxaˈmjaðo]; Portuguese: [alʒɐmiˈaðu]; Arabic: عَجَمِيَة trans. ʿajamiyah [ʕadʒaˈmij.ja]) or Aljamía texts are manuscripts that use the Arabic script for transcribing European languages, especially Romance languages such as Old Spanish or Aragonese. This alphabet is also called the Morisco alphabet.

According to Anwar G. Chejne, Aljamiado or Aljamía is "a corruption of the Arabic word ʿajamiyah (in this case it means foreign language) and, generally, the Arabic expression ʿajam and its derivative ʿajamiyah are applicable to peoples whose ancestry is not of Arabian origin". During the Arab conquest of Persia, the term became a pejorative.

The systematic writing of Romance-language texts in Arabic scripts appears to have begun in the fifteenth century, and the overwhelming majority of such texts that can be dated belong to the sixteenth century. A key aljamiado text is the compilation Suma de los principales mandamientos y devediamentos de nuestra santa ley y sunna by the mufti of Segovia, of 1462.

In later times, Moriscos were banned from using Arabic as a religious language, and wrote in Spanish on Islamic subjects. Examples are the Coplas del alhichante de Puey Monzón, narrating a Hajj, or the Poema de Yuçuf on the Biblical Joseph (written in Aragonese).

Aljamiado played a very important role in preserving Islam and the Arabic language in the life of the Moriscos of Castile and Aragon; Valencian and Granadan Moriscos spoke and wrote in Andalusi Arabic. After the fall of the last Muslim kingdom on the Iberian peninsula, the Moriscos (Muslims in parts of what was once Al-Andalus) were forced to convert to Christianity or leave the peninsula. They were forced to adopt Christian customs and traditions and to attend church services on Sundays. Nevertheless, some of the Moriscos kept their Islamic belief and traditions secretly, and this included the usage of Aljamiado.

In 1567, Philip II of Spain issued a royal decree in Spain, which forced Moriscos to abandon using Arabic on all occasions, formal and informal, speaking and writing. Using Arabic in any sense of the word would be regarded as a crime. They were given three years to learn the language of the Christian Spanish, after which they would have to get rid of all Arabic written material. Moriscos of Castile and Aragon translated all prayers and the Hadith (sayings of the Prophet Muhammad) into Aljamiado transcriptions of the Spanish language, while keeping all Qur'anic verses in the original Arabic. Aljamiado scrolls were circulated amongst the Moriscos. Historians came to know about Aljamiado literature only in the early nineteenth century. Some of the Aljamiado scrolls are kept in the Spanish National Library in Madrid.

Notes:

Spanish has 5 vowels, which include [a], [e], [i], [o], [u].