The announcement was made following a meeting of the central and zonal Ruet-e-Hilal committees for sighting the crescent of the Islamic month in Peshawar.
The meeting of the Central Ruet-e-Hilal committee was chaired by Maulana Abdul Khabir Azad in Peshawar, while the Khyber-Pakhtunkhwa (K-P) zonal moon-sighting committee also met at the same venue.
Meetings of other zonal committees were also held in Karachi, Islamabad, Lahore and Quetta simultaneously.
Meanwhile, Ramadan has already begun in several parts of the world, including the Middle East and Europe.
Several other countries have already announced March 12 as the beginning of Ramadan, including Australia, Malaysia, Philippines and Brunei.
Oman, too, has announced that it will observe the beginning of Ramadan on March 12, as there was no sighting of the crescent moon on Sunday evening.
Ramadan-ul-Mubarak, the month of fasting, is the ninth month of the Islamic lunar calendar.
During the fast, Muslims must abstain from eating, drinking, gossiping, and cursing, and are encouraged to focus on meditative practices like prayers, reading the Holy Quran and giving charity.