Public holidays mean a lot of governmental offices, shops, banks, embassies closed which may affect your travel in Cambodia. Some hotels require compulsory dinner on certain occasions. Some public holidays in Cambodia are based on the Gregorian Calendar and most based on the Lunar Calendar. Some important festivals and events are as follows:

Khmer New Year : mid April with 3-day celebration and people are off from work.
This is the time when people clean and decorate their houses, offer food to monks and exchange gifts. Everyone is armed with water to bless others encountered on the streets. Be prepared to get wet if you are in the country at this time. If you like to have tranquility exploring the temples and pagodas, then this is not a good time to travel in Cambodia.

International Workers' Day: May 1st.

Royal Ploughing Day: Early May.
The ceremony takes place in front of the National Museum where the King drives an ox to plough the field. The ox is given food and beverage and  based on what the ox consumed the result of the coming crop will be foretold.

Vesak Bucha Day: Late May.
This is the anniversary of the birth, enlightenment, and passing away of Buddha.

P'chum Ben: A very important religious ceremony in between mid September to early October.
On this day, everyone pays respect and rememberance to the spirit of dead relatives and friends. People would visit wats to pay offerings and pray. The Khmer believes that those who do not follow the practice of P'chum Ben are cursed by angry souls.

King Sihanouk's Birthday:  October 30th to November 1st
 Cambodians would flock to Phnom Penh to celebrate the reverenced King's birth day.

Water Festival :  late October or early November
The occasion marks the reversal of the Tonle Sap River so that it again empties into the Mekong River. The highlights of the three-day festival are the boat races held in Phnom Penh and Siem Reap.

Independence Day: November 9th
This celebrates Cambodia's independence from France in 1953.  The main ceremony takes place at the site of the Independence Monument in Phnom Penh.

Chinese New Year: January or February
 
National Day: January 7th
This day marks the end of the Khmer Rouge Regime.