Sinhalese New Year, generally known as Aluth Avurudda in Sri Lanka, is the new year of the Sinhalese people in Sri Lanka. It is a major anniversary celebrated by not only the Sinhalese people but by most Sri Lankans. The timing of the Sinhala New Year coincides with the new year celebrations of many traditional calendars of South and Southeast Asia. The festival has close semblance to the Tamil New year Thai New year, Bengali New Year, and Oriya New Year festival in India. It is a public holiday in Sri Lanka. It is generally celebrated on 13th or 14th April 2012.

According to Sinhalese astrology, New Year begins when the sun moves from Meena Rashiya (the house of Aries) to Mesha Rashiya. It also marks the end of the harvest and spring.

Cultural anthropological history of the 'Traditional New Year' which is celebrated on month of April, goes back to an ancient period in Sri Lankan history. Various beliefs, perhaps those associated with fertility of the harvest, gave birth to many rituals, customs, and ceremonies connected with the New Year. The advent of Buddhism in the 3rd century BC led to a re-interpretation of the existing New Year activities in the Buddhism light^{[citation needed]}. The majority of the people in the country are Buddhists, and as such, it is that the Buddhist outlook was predominant in transforming the New Year rites to what they are now.

New Year is the time at which a new calendar year begins and the calendar's year count is incremented. In many cultures, the event is celebrated in some manner. The New Year of the Gregorian calendar, today in worldwide use, falls on 1 January, as was the case with the Roman calendar. There are numerous calendars that remain in regional use that calculate the New Year differently.

The order of months in the Roman calendar was January to December since King Numa Pompilius in about 700 BC, according to Plutarch and Macrobius. According to Catholic tradition, 1 January is the day of the circumcision of Jesus (on the eighth day from his birth), when the name of Jesus was given to him (Luke 2:21).

It was only relatively recently that 1 January again became the first day of the year in Western culture. Until 1751 in England and Wales (and all British dominions) the new year started on 25 March – Lady Day, one of the four quarter days (the change to 1 January took place in 1600 in Scotland). Since then, 1 January has been the first day of the year. During the Middle Ages several other days were variously taken as the beginning of the calendar year (1 March, 25 March, Easter, 1 September, 25 December).^{[citation needed][where?]} In many countries, such as the Czech Republic, Italy and the UK, 1 January is a national holiday.