The romanization of Arabic is the systematic rendering of written and spoken Arabic in the Latin script. Romanized Arabic is used for various purposes, among them transcription of names and titles, cataloging Arabic language works, language education when used instead of or alongside the Arabic script, and representation of the language in scientific publications by linguists. These formal systems, which often make use of diacritics and non-standard Latin characters, are used in academic settings for the benefit of non-speakers, contrasting with informal means of written communication used by speakers such as the Latin-based Arabic chat alphabet.

Different systems and strategies have been developed to address the inherent problems of rendering various Arabic varieties in the Latin script. Examples of such problems are the symbols for Arabic phonemes that do not exist in English or other European languages; the means of representing the Arabic definite article, which is always spelled the same way in written Arabic but has numerous pronunciations in the spoken language depending on context; and the representation of short vowels (usually i u or e o, accounting for variations such as Muslim and Moslem or Mohammed, Muhammad and Mohamed).

Romanization is often termed "transliteration", but this is not technically correct.^{[citation needed]} Transliteration is the direct representation of foreign letters using Latin symbols, while most systems for romanizing Arabic are actually transcription systems, which represent the sound of the language, since short vowels and geminate consonants, for example, do not usually appear in Arabic writing. As an example, the following rendering “munāẓaratu l-ḥurūfi l-ʻarabīyah” of Arabic: مناظرة الحروف العربية is a transcription, indicating the pronunciation; an example transliteration would be mnaẓrḧ alḥrwf alʻrbyḧ.

Principal standards and systems are:

Early Romanization of the Arabic language was standardized in the various bilingual Arabic-European dictionaries of the 17–19th centuries:

Any romanization system has to make a number of decisions which are dependent on its intended field of application.

One basic problem is that written Arabic is normally unvocalized; i.e., many of the vowels are not written out, and must be supplied by a reader familiar with the language. Hence unvocalized Arabic writing does not give a reader unfamiliar with the language sufficient information for accurate pronunciation. As a result, a pure transliteration, e.g., rendering قطر as qṭr, is meaningless to an untrained reader. For this reason, transcriptions are generally used that add vowels, e.g. qaṭar. However, unvocalized systems match exactly to written Arabic, unlike vocalized systems such as Arabic chat, which some claim detracts from one's ability to spell.

Most uses of romanization call for transcription rather than transliteration: Instead of transliterating each written letter, they try to reproduce the sound of the words according to the orthography rules of the target language: Qaṭar. This applies equally to scientific and popular applications. A pure transliteration would need to omit vowels (e.g. qṭr), making the result difficult to interpret except for a subset of trained readers fluent in Arabic. Even if vowels are added, a transliteration system would still need to distinguish between multiple ways of spelling the same sound in the Arabic script, e.g. alif ا vs. alif maqṣūrah ى for the sound /aː/ ā, and the six different ways (ء إ أ آ ؤ ئ) of writing the glottal stop (hamza, usually transcribed ʼ ). This sort of detail is needlessly confusing, except in a very few situations (e.g., typesetting text in the Arabic script).