The general secretary of the Communist Party of Vietnam, Nguyen Phu Trong, will pay a state visit to Cambodia from Thursday until Saturday.
The Foreign Affairs Ministry said Mr Trong would be given a royal audience by King Norodom Sihamoni and the Queen Mother Norodom Monineath Sihanouk.
Mr Trong will also meet Senate leader Say Chhum, National Assembly President Heng Samrin, as well as the Great Supreme Patriarchs Tep Vong and Bour Kry.
Prime Minister Hun Sen will hold an official meeting with Mr Trong, in which a number of deals are expected to be signed.
“After the meeting, both leaders will preside over a signing ceremony for a joint statement on strengthening Cambodia-Vietnam friendship and cooperation, plus a number of documents,” the ministry said.
Mr Chhum and Mr Trong will also oversee the inauguration of a Cambodia-Vietnam Friendship monument in Preah Sihanouk province.