The blast reportedly took place in a mosque in the Khair Khana area during evening prayers.
According to witnesses, the powerful explosion was heard in a northern Kabul neighbourhood, shattering windows in nearby buildings. Ambulances were then rushed to the spot.
There was no immediate claim of responsibility for the attack, the latest to strike the country in the year since the Taliban seized power.
Among the dead is a top Islamic cleric named Amir Mohammad Kabuli. A resident of the city's Kher Khanna neighborhood where the Siddiquiya Mosque was targeted said that the explosion was carried out by a suicide bomber.