The appeal was made on the sidelines of the UN General Assembly in New York on Wednesday by the US, Australia, Canada, European Union, France, Germany, Italy, Japan, Saudi Arabia, the United Arab Emirates, the UK and Qatar.
"The situation between Lebanon and Israel since October 8, 2023, is intolerable and presents an unacceptable risk of broader regional escalation. This is in no one's interest, neither the people of Israel nor Lebanon," according to a joint statement of the countries.
The allies emphasised that diplomacy cannot succeed amid continued conflict.
"It is time to conclude a diplomatic settlement that allows civilians on both sides of the border to return to safety," the statement added.
The joint call urged for the 21-day ceasefire to provide space for diplomatic negotiations, in line with UN Security Council Resolution (UNSCR) 1701, which ended the 2006 Israel-Hezbollah war, and the implementation of UNSCR 2735 regarding a ceasefire in Gaza.
"We call on all parties, including the governments of Israel and Lebanon, to immediately endorse the ceasefire and give diplomacy a real chance to resolve the crisis," the statement urged.
The countries also expressed readiness to support diplomatic efforts to secure a final agreement between Lebanon and Israel within the ceasefire period.
While there has been no immediate response from Israel, Lebanon, or Hezbollah, senior US officials confirmed that all parties were aware of the ceasefire call.
Representatives from Israel and Lebanon had earlier reaffirmed their commitment to the UN resolution that ended the 2006 conflict between Israel and Hezbollah.
US Secretary of State Antony Blinken is expected to meet with Israeli Prime Minister Benjamin Netanyahu's top strategic adviser in New York on Thursday ahead of the prime minister's arrival.
Netanyahu has signalled openness to pursuing a deal, provided it includes the return of Israeli civilians to their homes, according to some media reports.
This conflict follows the deadly October 7, 2023 Hamas attack on southern Israel, which killed about 1,200 people and resulted in hostages being taken.
Israel's military response has since led to over 41,000 Palestinian deaths, according to Gaza health officials.