The Mongolian language (in Mongolian script: ,Mongγol kele; in Mongolian Cyrillic: Монгол хэл, Mongol khel) is the official language of Mongolia and the best-known member of the Mongolic language family. The number of speakers across all its dialects may be 5.2 million, including the vast majority of the residents of Mongolia and many of the Mongolian residents of the Inner Mongolia autonomous region of China. In Mongolia, the Khalkha dialect, written in Cyrillic, is predominant, while in Inner Mongolia, the language is more dialectally diverse and is written in the traditional Mongolian script. In the discussion of grammar to follow, the variety of Mongolian treated is Standard Khalkha Mongolian (i.e., the standard written language as formalized in the writing conventions and in the school grammar), but much of what is to be said is also valid for vernacular (spoken) Khalkha and other Mongolian dialects, especially Chakhar.

Mongolian has vowel harmony and a complex syllabic structure for a Mongolic language that allows clusters of up to three consonants syllable-finally. It is a typical agglutinative language that relies on suffix chains in the verbal and nominal domains. While there is a basic word order, subject–object–predicate, ordering among noun phrases is relatively free, so grammatical roles are indicated by a system of about eight grammatical cases. There are five voices. Verbs are marked for voice, aspect, tense, and epistemic modality/evidentiality. In sentence linking, a special role is played by converbs.