Yemeni Arabic (Arabic: لهجة يمنية, romanized: Lahja Yamaniyyah, lit. 'Yemeni dialect') is a cluster of varieties of Arabic native to Yemen and southwestern Saudi Arabia. It is generally considered a very conservative dialect cluster, having many classical features not found across most of the Arabic-speaking world.

Yemeni Arabic can be divided roughly into several main dialect groups, each with its own distinctive vocabulary and phonology. The four most important groups are San'ani in the North and Centre and Hadhrami in the East, where ⟨ق⟩ is pronounced [g] and ⟨ج⟩ is [d͡ʒ] or [ʄ] (except in coastal Hadhrami where ⟨ج⟩ is [j]), in addition to Ta'izzi-Adeni in the South and Tihami in the West, where ⟨ق⟩ is [q] and ⟨ج⟩ is [g]. Yemeni Arabic is used for daily communications and has no official status; Modern Standard Arabic is used for official purposes, education, commerce and media.

Non-Arabic South Semitic languages indigenous to the region include several Modern South Arabian languages, such as the Mehri and Soqotri languages, which are members of an independent branch of the Semitic family. Another separate Semitic family once spoken in the region is Old South Arabian; these became extinct in the pre-Islamic period with the possible exceptions of Razihi and Faifi. Some of these share areal features with Yemeni Arabic owing to influence from or on Yemeni Arabic.

Yemeni Arabic itself is influenced by Himyaritic, Modern South Arabian and Old South Arabian languages and possesses significant substratum from these languages.

Tihamiyya Arabic has many aspects that differentiate it from all other dialects in the Arab world. Phonologically Tihami is similar to the majority of Yemeni dialects, pronouncing the qāf (ق) as [q] and the ǧīm (ج) as a velar plosive [ɡ] (the ǧīm pronunciation is also shared with Egyptian Arabic and most Omani Arabic dialects). Grammatically, all Tihami dialects also share the unusual feature of replacing the definite article (al-) with the prefix (am-). The future tense, much as in the dialects surrounding Sana'a, is indicated with the prefix (š-) for all persons, e.g. šabūk am-sūq "I shall go to the market”. Some Tihami dialects, such as that spoken in al Hudaydah, are otherwise fairly similar to other Yemeni dialects in grammar and syntax, differing mainly in vocabulary, while others can be so far from any other Arabic dialect that they are practically incomprehensible even to other Yemenis.

Of all the dialects of the Tihama region, the dialect of Zabid displays the most innovations. It shares the transformed definite article of (am-) originally used in Himyaritic with the rest of the Tihami dialects, but it is unique in retaining certain of the declensional suffixes in the nominative case. Indefinite masculine nouns in nominal sentences as well as the subjects of verbal sentences are suffixed with the sound (-ū), which stems from the classical suffix (-un/-u). Likewise the phonology of the Zabidi sub-dialect replaces the sound (ʿain) [ʕ] (ع) with the glottal stop ( ʾ ) [ʔ] (ء). In terms of vocabulary, the Zabidi dialect shares very little with other Arabic dialects, in many respects seeming to be a different language. Zabidis use the verb bāka, yabūk, to mean ‘to go’, the word goh#d and goh#da to mean ‘man’ and ‘woman’ respectively and the word fiyān to mean ‘where’, hence the phrase: fiyān bāyku? meaning ‘Where are you going?’, which is grammatically parallel to the more familiar: wayn rāyih? of more mainstream dialects. (citation?)

The Hadhrami dialect in many towns and villages in the Wādī (valley) and the coastal region is characterised by its pronunciation of the voiced palatal plosive (or affricate) (ج) as the semi-vowel (ي) (y) ([j]). In this it resembles some Eastern Arabian and Gulf dialects including the dialects of Basra in Iraq, Kuwait, Qatar, Bahrain and the other Arab Emirates. In educated speech (ج) is realised as a voiced palatal implosive ([ʄ]) or affricate ([dʒ]) in some lexical items.

The ق [q] reflex is pronounced as a voiced velar [ɡ] in all lexical items throughout the dialect. With the spread of literacy and contact with speakers of other Arabic dialects, future sociolinguistic research may reveal whether HA is going to witness innovation such as using the uvular /q/ in certain lexemes while retaining the velar /ɡ/ for others.