Prime Minister Hassan Diab made the announcement in a television address on Monday evening.
The Lebanese government has resigned over last week's deadly blast at Beirut's port.
Prime Minister Hassan Diab made the announcement in a television address on Monday evening, saying he and his cabinet were stepping down in the wake of the Beirut port explosion last week that triggered public fury and mass protests.
In a brief speech on national TV, the leader said he is taking "a step back" so he can stand with the people "and fight the battle for change alongside them."
"I declare today the resignation of this government. May God protect Lebanon," he added, repeating the last phrase three times.
Health Minister Hamad Hassan told reporters the decision was made under increasing pressure as several ministers quit or expressed their intention to step down.
Justice minister Marie Claude Najm resigned earlier on Monday, according to the state-run National News Agency.
His Cabinet now assumes the caretaker role until a new government is formed.
The move came after two days of demonstrations in Beirut over the weekend that saw clashes with security forces firing tear gas at protesters.¨
A Lebanese judge on Monday began questioning the heads of the country's security agencies over the explosion, starting with the head of state security, Major General Tony Saliba, the National News Agency said.
Dozens of people have been questioned, including two former Cabinet ministers, according to government officials.
Violent protests broke out following the explosion, which killed at least 160 people, that many Lebanese people blamed on government negligence.
Protesters clashed with security forces and managed to break into several government buildings and an association of banks.
Officials have said that the explosion was in part caused by the ignition of 2,750 tonnes of ammonium nitrate that had been sitting in Beirut's port for years.
Protesters and critics are demanding answers over how the substance came to be stored at the port and why nothing was done about it.
Around 20 people have been detained over the blast, including the head of the port and the chief of Lebanon’s customs department and his predecessor.
French President Emmanuel Macron, who visited Beirut in the wake of the blast, said the international community should stand for "a credible independent impartial investigation into the causes of the August 4 disaster."
Around 6,000 people were wounded in the explosion and nearly 300,000 people were left homeless in the immediate aftermath.
Lebanon's main port was left destroyed and large swathes of Beirut were damaged.