Thailand and Cambodia's leaders agreed to an "unconditional" ceasefire on Monday, after five days of combat along their border that has killed at least 36 people.
Nearly 300,000 people have fled as the two sides fired artillery, rockets and guns in a battle over the long-disputed area, which is home to a number of ancient temples.
Malaysian Prime Minister Anwar Ibrahim, who chaired the peace talks, said they had agreed "an immediate and unconditional ceasefire" with effect from midnight Monday.
The truce was agreed by Thai acting Prime Minister Phumtham Wechayachai and Cambodia's Prime Minister Hun Manet.
US President Donald Trump intervened over the weekend, and said both sides had agreed to "quickly work out" a truce.
Mr Trump had threatened to stop trade deals until the two countries stopped fighting.
Each side had already agreed to a truce in principle, while accusing the other of undermining peace efforts and trading allegations about the use of cluster bombs and targeting of hospitals.
Thailand says nine of its soldiers and 14 civilians have been killed, while Cambodia has confirmed eight civilian and five military deaths.
The Thai military said it had returned the bodies of 12 Cambodian soldiers killed in combat.
