A wave of bomb attacks has swept across Pakistan, killing more than 180 people, since the army's siege and assault earlier this month on the Lal Masjid or Red Mosque complex in the capital Islamabad.
Thursday night's blast hit as Muslim worshippers were going to offer night prayers in the Pathan Centre market area in Kohat a military stronghold about 150km west of the capital, Islamabad.
A local police official said: "Fourteen people were killed and at least 19 others were injured in the blast in a mosque."
"It appears to be a suicide blast," he said.
Earlier on Thursday, two explosions in Pakistan, one in the south and the other in the northwest, killed about 36 people, mostly police.
A suicide bomber had blew himself up at a police training centre in the northwestern city of Hangu, killing seven.
Later, a bomb blast in a market place in the southern town of Hub, on the border between Sindh and Baluchistan provinces, killed at least 25 people, including seven police.