Arabic exhibits diverse dialectal varieties shaped by geographical, social, cultural, and historical conditions. This study describes the use and characteristics of four major Arabic dialect groups: Levantine (Shāmiyyah), Egyptian, Maghrebi, and Gulf (Khalījiyyah) Arabic. It examines linguistic differences among these groups and their implications for teaching Arabic as a foreign language. The study employs library research, with data collected through documentation and literature review. The data comprise studies on Arabic dialects and their implications for foreign-language teaching, while sources include books, journals, scholarly articles, previous studies, conference papers, reports, and relevant audiovisual materials. Data were analyzed through content analysis by examining, comparing, and interpreting information from various sources to identify usage characteristics and linguistic differences across the dialect groups. Findings indicate that differences are primarily evident in phonology, vocabulary, and linguistic structures. In Egyptian Arabic, the phoneme qāf (ق) may be realized as a glottal stop (ء), while in some Maghrebi varieties, particularly Moroccan Darija, qāf (ق) may be realized as /g/. Some Levantine varieties also show phonological changes, such as the realization of dhāl (ذ) as dāl (د). Despite these differences, all four groups maintain a close relationship with Modern Standard Arabic (MSA). Dialectal variation is influenced by geography, society, culture, migration, language contact, and language-use patterns. Such diversity has significant implications for foreign-language teaching because differences in pronunciation, vocabulary, and structures may challenge learners communicating with native speakers. Therefore, understanding MSA and dialectal variations in contextual use is essential for developing learners’ Arabic communicative competence in real-life situations.