June 18 is the birthday of Queen Mother Norodom Monineath Sihanouk (Khmer: នរោត្ដម មុនីនាថ សីហនុ) and is a public holiday in Cambodia. Born Paule Monique Izzi into a wealthy Cambodian family, she met King Norodom Sihanouk in 1951 when he awarded her first prize in a beauty contest. They married privately a year later.

Cambodia is an elective constitutional monarchy, in which a King rules along side a Prime Mister similar to the United Kingdom and other countries.

After the coup of 1970, Monineath and her husband were given asylum in China and North Korea. They returned to Cambodia in 1975 and her husband was appointed nominal head of state by the Khmer Rouge. They were, however, kept in house arrest and finally had to be evacuated by the Chinese 1979.

The couple returned to Cambodia in 1991 when a United Nations-brokered truce restored some stability to the country. Her husband reigned as king until 2004 when he abdicated his throne. His son, Norodom Sihamoni (Khmer:នរោត្តម សីហមុនី; born 14 May 1953) was named King by a nine-member throne council.

Monineath speaks Khmer, French, and English. She is the Cambodian Red Cross Honorary President.