The grammatical category grammatical aspect refers to the internal temporal syntax of a verb phrase. As opposed to the lexical aspect, the grammatical aspect is not a semantic feature, and is only then valid for a verb phrase if it is applied as predicate.

The grammatical aspect appears in the following subcategories:

1. The perfective grammatical aspect is only valid for dynamic verb phrases indicating one-time events:
   • A punctual verb phrase in the perfective refers to a non-recurrent event whose execution time is expressed by the tense of the verb phrase:

     آخرهایِ مسابقه حسین از من جلو زد. (past)

     آخرهایِ مسابقه حسین از من جلو خواهد زد. (future)

     It is notable that verb phrases can also appear as punctual and in the perfective, even when their verbal roots are stative. In this case, the verb phrase refers only to the start time of the expressed state:

     او از تهدیدهایِ مردِ نقاب‌دار ترسید (= ترس برش داشت).

     دانست (= متوجّه شد) که برادرش به او دروغ می‌گوید.

     پدرم خوابید (= به خواب فرو رفت).

   • Application of durative verb phrases in the perfective indicates that both the start point and the end point of a non-recurring event lie in the tense of the verb phrase:

     دیروز یک دست لباس دوختم. (past)

     فردا یک دست لباس می‌دوزم. (future)

     فردا یک دست لباس خواهم دوخت. (future)

2. All other verb phrases are in the imperfective. This grammatical aspect subcategory refers to an act regardless of its termination. It is classified as follows, but note that these subcategories are to a large extent realized in Indo-European languages with the same syntactical pattern:
   • All verb phrases in the stative lexical aspect are also in the stative grammatical aspect:

     فرهاد می‌خواست (past) خلبان بشود.

     شیراز از زیباترین شهرهایِ ایران است. (present)

     شیراز از زیباترین شهرهایِ ایران می‌باشد. (present)

   • Verb phrases in the iterative are dynamic and refer to acts which recur perpetually:

     پدرم دوشنبه‌ها ناهارش را سرِ کار می‌خورد. (durative and in the present)

     او هر روز با سر و صورتِ زخمی به خانه می‌رسید. (punctual and in the past)

   • Verb phrases in the habitual are durative; they indicate acts happening usually:

     او ماه‌ها این جا کار می‌کرد. (past)

     با بدی‌هایِ تو می‌سازم. (present)

   • Verb phrases in the progressive indicate the perpetual process of an act at a time which is expressed by the tense of the verb phrase:

     روزنامه می‌خواند (past) که از صدایِ در از جا پرید.

     در خراباتِ مغان نورِ خدا می‌بینم (present)

     این عجب بین که چه نوری زِ کجا می‌بینم! (present)

     Hafez (14^th Century AD)

     It is notable that modern idioms of Persian have developed specific syntactical patterns to express the progressive grammatical aspect:

     • The verbal root /dɒʃ/ (infinitive /dɒʃtæn/ داشتن) is applied among others with the meaning “proceed”:

       یلان را به پیکار و کین بر گماشت

       به سد حیله آن رزم تا شب بداشت

       Asadi Tusi (11^th Century AD)

       اگر سده بسیار باشد، تب سه شبان‌روز بدارد، و اگر کمتر باشد، زودتر گسارد.

       Esmail Gorgani (11^th and 12^th Century AD)

       به جایِ خویش بنشست و مردمان را معذرت می‌کرد و باز می‌گردانید، و تا شب بداشت.

       Abolfazl Beyhaqi (10^th and 11^th Century AD)

       In western idioms, patterns for progressive are generated by means of subordination with content clause with a modal verb with the infinitive /dɒʃtæn/ داشتن (see 18•۲•e•b•d.):

       او دارد کتاب می‌خواند. (present)

       وقتی تلفن زنگ زد، پدرم داشت نامه می‌نوشت. (past)

       داشتم سوارِ تاکسی می‌شدم (past) تا بر گردم خانه که یک دفعه به صرافت افتادم که «اقلاًّ چرا نپرسیدی چه بلایی به سرش آمده؟».

       Jalal Al-e Ahmad (20^th Century AD)

     • In the Tajik idiom, perfect participles are compound with verb phrases from the verbal root /ist/ (infinitive /istɒdæn/ ایستادن) in the pre-present and pre-past tense to perform this function (see “Tadschikische Studiengrammatik” by Prof. Dr. Lutz Rzehak, page 78 to 90, and the article of Firuza Amanova in مجلهء زبانشناسی, ۱۵^th and 16^th issue, page 5 and 6):

       رفته ایستاده‌ام. (present)، گفته ایستاده بود. (past)

     One feature of Persian is that, as opposed to most of other Indo-European languages, progressive verb phrases appear in the affirmative form.