Malayalam is one of the Dravidian languages and has an agglutinative grammar. The word order is generally subject–object–verb, although other orders are often employed for reasons such as emphasis. Nouns are inflected for case and number, whilst verbs are conjugated for tense, mood, and causativity (and also in archaic language for person, gender, number, and polarity). Malayalam adjectives, adverbs, postpositions, and conjunctions do not undergo any inflection; they are invariant.

The declensional paradigms for some common nouns and pronouns are given below. As Malayalam is an agglutinative language, it is difficult to delineate the cases strictly and determine how many there are, although seven or eight is the generally accepted number. Alveolar plosives and nasals (although the modern Malayalam script does not distinguish the latter from the dental nasal) are marked with a macron below, following the convention of the National Library at Kolkata romanization.

There are three persons – first, second, and third. The first person has three forms – singular, inclusive plural (i.e. speaker, listener, and possibly others), and exclusive plural (i.e. speaker and others, but not the listener). The second person has three forms – singular informal, singular formal and plural. Of these, the singular formal and, plural forms are similar. A fourth form ('respectful' or 'official') is sometimes used in certain official documents and announcements.

The third person has eight forms – proximal and distal forms of singular masculine, singular feminine, singular neutral and plural. The masculine and feminine genders are used for humans and anthropomorphised non-humans. Non-living objects, plants and most animals take the neutral gender. The plural form is used for multiple objects of any gender. The plural form can also be used for a single person to show respect or because the gender is unknown or irrelevant.

Vocative forms are given in parentheses after the nominative, as the only pronominal vocatives that are used are the third person ones, which only occur in compounds.

The mnemonic 'നിപ്രസം ഉപ്രസം ആ' (niprasam uprasam ā) created by combining the first sounds of the case names is used.

The suffix -കൾ (-kaḷ), which changes to -ങ്ങൾ (-ṅṅaḷ) when the nouns ends in -അം (-aṁ), is the most common suffix for denoting plural nouns. It is used by all inanimate nouns, concrete or abstract, and most animate, non-gendered nouns. Two other suffixes, -മാർ (-māṟ) and അർ (-aṟ), are used exclusively by a few animate nouns. All suffixes follow the sandhi (സന്ധി) rules where applicable, and are not used when preceded by numeral adjectives. The following are a few examples.

The following are examples of some of the most common declensional patterns.