Foreign donors have made clear there will be no aid until Beirut makes changes to tackle state waste and corruption - roots of the crisis, which poses the biggest threat to Lebanon's stability since a 1975-1990 civil war.
"Given the absence of an effective will to achieve structural, comprehensive reform which our society and the international community have urged us to do, I have decided to resign," Hitti said in a statement.
President Michel Aoun and Prime Minister Hassan Diab accepted the resignation and appointed Charbel Wehbe, Aoun's diplomatic adviser since 2017, as foreign minister, said two decrees read out by the cabinet's secretary general.
Wehbe, 67, is a former secretary general of the foreign ministry.
Hitti, a former ambassador to the Arab League, was appointed in January when Diab's cabinet took office with the support of the Iran-backed Hezbollah movement and its allies.
"I took part in this government to work for one boss called Lebanon, then I found in my country multiple bosses and contradictory interests," Hitti said. "If they do not come together in the interest of rescuing the Lebanese people, God forbid, the ship will sink with everyone on it."
He also had differences with Diab and was frustrated at being sidelined, sources close to the ministry told Reuters. Diab appeared to criticize France's foreign minister for tying aid to reforms and a deal with the International Monetary Fund (IMF) when visiting Beirut last month.
A spokesperson for Diab's office told Reuters the cabinet was now focused on moving ahead with a forensic audit of the central bank and "a wide range of other reforms."
Talks with the IMF, which the heavily indebted state entered in May after a sovereign default, are on hold.
Two members of Lebanon's negotiating team have quit in protest at the handling of the crisis.Hopes of an IMF deal have been hamstrung by a row over the scale of vast financial losses between the government, the banking sector and lawmakers from the main parties.