The subjunctive is the mood of subjectivity, dependence and non-assertive evaluation. It appears especially in subordinate clauses introduced by verbs, phrases and conjunctions that express will, doubt, emotion, necessity or purpose. In spoken Italian the indicative is often used instead of the subjunctive, but the subjunctive remains central in formal register and in writing.

The subjunctive is often required after verbs of will and desire, such as to want, to desire, to hope and to prefer, when the subject of the subordinate clause does not coincide with that of the main clause. It also appears after verbs of doubt and negation, such as doubt, not believe, not think and fear, because the following clause is not presented as a certain fact. After verbs of emotion and evaluation, such as being happy, to be surprised, to feel sorry and to please, the subjunctive signals a subjective reaction to content not treated as an objective fact.

Some conjunctions introduce subordinate clauses that require the subjunctive because they express limit, condition, purpose or perceived anteriority. Among the most common are benché, sebbene, purché, affinché and prima che. In constructions such as a meno che non, the negation often accompanies the conjunction and the subordinate clause stays in the subjunctive.

Impersonal constructions that express necessity, opportunity or possibility favor the use of the subjunctive in the subordinate clause introduced by che. Phrases such as è necessario, è importante, è possibile and sembra che present the content as required, desired or only probable. This usage is very common in formal texts and in many standard varieties of Italian.

The present subjunctive expresses contemporaneity with respect to the main clause and is formed with che followed by the specific person forms. The most frequent forms show regular bases such as sia, parli and finisca. It is the typical choice when the content of the subordinate clause is required, desired, doubted or evaluated in the present.

The imperfect subjunctive is used for contemporaneity in the past, for unreality and for dependencies conditioned by a past time. Forms such as fosse, parlassi and finissi are typical after past-tense governing verbs or in structures that maintain distance from the real. For hypothetical values it is often linked to the conditional, as happens in the Simple Conditional.

The past subjunctive is formed with the present subjunctive of the auxiliaries avere or essere and the past participle. The pluperfect subjunctive uses the imperfect subjunctive of the auxiliaries and indicates anteriority relative to another past or to a non-real situation already past. The choice of tenses follows the sequence of tenses, which is flexible in speech but more controlled in written register.

Some very frequent verbs have irregular or particular forms in the subjunctive and must be recognized as stable lexical cores. Among the most important are essere, avere, andare, fare, dare and stare. These forms often appear in the borderline contexts of the subjunctive and help to distinguish precisely the tenses and the logical relations of the subordinate clause.

The subjunctive is chosen when the subordinate clause is presented as subjective, desired, doubtful, evaluated or non-factual. If the speaker states a fact with greater certainty or in a colloquial style, the indicative can replace it, especially in speech. The agreement of tenses and the level of formality guide the final choice, with more attention to precision in formal writing and expository texts.