Portuguese verbs display a high degree of inflection. A typical regular verb has over fifty different forms, expressing up to six different grammatical tenses and three moods. Two forms are peculiar to Portuguese within the Romance languages:

• The personal infinitive, a non-finite form which does not show tense, but is inflected for person and number.
• The future subjunctive, is sometimes archaic in some dialects (including peninsular) of related languages such as Spanish, but still active in Portuguese.

This article does not cite any sources. (September 2017)

It has also several verbal periphrases.

Portuguese verbs have the following properties.

1. Two numbers—singular, plural
2. Three persons—first, second, third
3. Three aspects—perfective, imperfective, progressive*
4. Two voices—active, passive*
5. Six morphological forms for tenses, aspects, and/or moods—present, preterite, imperfect, pluperfect, future, and conditional.
6. Three (or four) moods—indicative, subjunctive, imperative (and conditional, according to some authors)

Classes with an asterisk are entirely periphrastic. The passive voice can be constructed in two different ways. The pluperfect and the future of the indicative mood, as well as the conditional form, are often replaced with other verbal constructions or verbal periphrases in the spoken language.

Conjugation is demonstrated here with the important irregular verb fazer, "to do":

Periphrastic forms are as follows:

Regular verbs belong to one of three conjugation classes, distinguished by the ending of their infinitive forms (which is also their citation form):

• Those whose infinitive ends in -ar belong to the first conjugation (e.g. lavar, matar, ladrar);
• Those whose infinitive ends in -er belong to the second conjugation (e.g. correr, comer, colher);
• Those whose infinitive ends in -ir belong to the third conjugation (e.g. partir, destruir, urdir);

The verb pôr is conventionally placed in the second conjugation by many authors, since it is derived from Old Portuguese poer (Latin ponere). In any event, this is an irregular verb whose conjugation must be learned on its own. Other verbs with infinitives ending in -or, such as depor, compor, and propor are derivatives of pôr, and are conjugated in the same way.

The following irregular verbs are used as auxiliary verbs in various periphrastic constructions.

There are few irregular verbs for these tenses (only dizer, fazer, trazer, and their compounds – also haver, ter, ser, ir, pôr, estar, etc. – for the subjunctive future imperfect). The indicative future imperfect, conditional, and subjunctive future imperfect are formed by adding to the infinitive of the verb the indicative present inflections of the auxiliary verb haver (dropping the h and av), the 2nd/3rd conjugation endings of the preterite, imperfect, and the personal infinitive endings, respectively. Thus, for the majority of verbs, the simple personal infinitive coincides with subjunctive future.

The affirmative imperative for second person pronouns tu and vós is obtained from the present indicative, by deletion of the final -s (in some cases, an accent mark must be added to the vowel which precedes it). For other persons, and for negative clauses, the present subjunctive takes the role of imperative.

In the present tense, the stress fluctuates between the root and the termination. As a rule of thumb, the last radical vowel (the one that can be stressed) will retain its original pronunciation when unstressed (atonic) and change into [a], [e/ɛ] (subjunctive or indicative 1st pers sing/infinitive), or [o/ɔ] (subjunctive or indicative 1st pers sing/infinitive) – depending on the vowel in question – in case it is stressed (is in a tonic syllable). Other vowels (u, i) and nasalized vowels (before closed syllables) stay unchanged, as well as the verbs with the diphthongs -ei, -eu, -oi, -ou; they always keep a closed-mid pronunciation; e.g. deixo /ej/ (deixar), endeuso /ew/ (endeusar), açoito /oj/ (açoitar), roubo /ow/ (roubar), etc. Alternation in stem-stressed forms is blocked when a nasal consonant (/m/, /n/ or /ɲ/) follows, in which case the higher alternant (i.e. /ɐ/, /e/ or /o/) is used in all forms. For example, in the verb comer, all of the forms como, comes, come, comem have /o/.

Example: Consider the conjugation of correr (analogous to comer, presented above) in the Indicative Present Simple. The first-person singular corro has [o] in the stressed vowel, while other forms corres, corre, correm have [ɔ].

In Brazil, the following difference applies: Stem-unstressed forms consistently have /o/ or /e/ for most speakers in most verbs, but there are exceptions, with some dialects (e.g. northeastern Brazilian dialects) likely to present an open form /ɔ/ or /ɛ/. At times, the difference is not particularly clear, producing [o̞], [e̞], particularly in transition zones like the states of Rio de Janeiro, Espírito Santo, Minas Gerais and the Brazilian Federal District, unless vowel harmony is involved (e.g. comove "move, touch (emotionally)" [kɔˈmɔvi]).

This also has repercussions in the imperative and present subjunctive, for their inflections are constructed from the indicative present simple and indicative present simple in the 1st singular person respectively.

This article should specify the language of its non-English content, using {{lang}}, {{transliteration}} for transliterated languages, and {{IPA}} for phonetic transcriptions, with an appropriate ISO 639 code. Wikipedia's multilingual support templates may also be used. (June 2021)

• Portuguese grammar
• Portuguese personal pronouns and possessives
• Portuguese phonology
• Wikibooks: Variation of the Portuguese Verbs