Greece's minister responsible for the police, Nikos Toskas, quit on Friday after scores died in wildfires near Athens last month, Prime Minister Alexis Tsipras' office said.
"The prime minister has accepted Mr Toskas' resignation," the PM's office said in a statement after a meeting with the minister.
Tsipras was under pressure to sack members of his administration after the fires at the coastal resort of Mati on July 23, the deadliest in Greek history.
The death toll has climbed to 88 people, many of them children, with another 40 in hospital and one still listed as missing.
Nine of the injured are in a critical condition.
Earlier on Friday, the wife of a fireman who had already lost her six-month-old baby in the disaster died in hospital from burn injuries, the health ministry said.
"The loss of so many of our fellow human beings at Mati has overcome my desire to continue," said Toskas, a former tank general who had held the job since 2015.
Opposition parties have accused the government of failing to provide adequate warning and evacuate an area frequently hit by wildfires, in addition to subsequently trying to hide the scale of the loss of human life as the disaster unfolded.
In the days that followed, the firefighters and police -- both departments under Toskas' responsibility -- issued conflicting announcements over what went wrong.
One police union this week said officers had not been promptly notified by the fire department of the fire's exact location in order to set up proper roadblocks in the area. As a result, many drivers were mistakenly diverted into the fire zone and died after becoming trapped in the area's narrow streets.
Officials were criticised for holding an emergency response meeting hours after the fire broke out, when Mati had already been overwhelmed.
There was also confusion for days over the exact number of dead and missing.
Toskas said he had offered to resign in the immediate aftermath of the fires, but had been told by Tsipras to stay until the end of the emergency.
The relatives of two people who perished in the fires have sued the authorities for negligence and exposure to danger.
The fires struck the coastal community popular with holidaymakers, burning with such ferocity that most people fled to the sea with just the clothes on their backs.
Toskas and other officials had insisted that with winds blowing at speeds of up to 120 kilometres per hour, there was little time to mount an effective evacuation.