Hausa Ajami script is an Arabic script derivative for writing the Hausa language. Ajami is a name commonly given to alphabets derived from Arabic script for the use of various African languages, from Swahili to Hausa, Fulfulde, and Wolof.

Hausa ajami is an alphabet where vowel sounds are written using a mixture of combining marks and letters. Unlike Semitic languages such as Arabic that build words on consonant patterns and so normally hide vowel diacritics in the Arabic script, it can be difficult to read Hausa text without the full vowel information, and therefore Hausa retains all vowel diacritics in the text.

In Niger and Nigeria, there exist two general orthographic traditions, each derived from two Quranic orthographic practices. One of these is based on the Quran recitation and inscription of the 8th century religious scholar Hafs ibn Sulayman, the other based on the Quran recitation and inscription of another 8th Century scholar, Warsh. Hafs tradition is the most popular across the Muslim world, and especially in Egypt, the Levant, and the Arabian Peninsula. Warsh tradition is the second most popular tradition across the Muslim world, and has been especially popular in North Africa, West Africa, and Andalusia. In Niger and Nigeria, Warsh is the orthographic convention preferred by local Sufi schools and scholars (including Tijaniyyah and Qadiriyya schools), whereas Hafs is the orthographic convention preferred by Sunni schools and scholars, including the Salafi Izala Society. While technically such distinction between Sufis and Sunnis does not theologically exist, this is a good approximation of the sociolinguistic situation.

While Hafs is generally always written in Naskh, Warsh is written either in Naskh, or in Maghrebi script, following North African traditions, and in a local calligraphic tradition.

From Nigerian independence up until 2007, the Hausa text on Nigerian naira banknotes were written in Warsh script. Prior to independence, British West African pound banknotes included Hausa text written in Hafs script.

The name 'Ajami' came to be used in such a way for the adoption of Arabic script to write a non-Arabic language in Africa. Originally, 'Ajami' referred to non-Arab language in Africa, as it did elsewhere in the Muslim world too, with Persian, Turkish, Malay, Spanish, etc. being referred to as 'Ajami'. Thus, in Northern Nigeria for example, languages such as Hausa and Fulfulde where referred to as 'Ajami languages'. Thus by extension, texts written in such languages were referred to as 'Ajami', simply meaning "foreign", and to be distinguished from texts written in Arabic. But, it was in colonial Northern Nigeria that the earlier notion of 'Ajami language' (Hausa, Fulfulde) was misinterpreted and transformed into 'Ajami script'.

It was within the context of this development that Mervyn Hiskett states that 'It [Hausa] is now written for official and scholastic purposes in the Roman script (with the addition of three special letters), but the older Arabic script (known as ajami) is still extensively used for private correspondence and religious tracts'.

Over time, this misrepresentation by European Christian missionaries, colonial officials, and Africologists, was adopted by native Hausa-speaking scholars as well. For example, famed Hausa linguist, Ibrahim Yaro Yahaya, uses 'Ajami' in such a way.