Various competing theories for the origins of the term boxing day circulate in popular culture, none of which is definitive. However, the Oxford English Dictionary gives the earliest attestations of the term as being from England in the 1830s, defining it as
- The first week-day after Christmas-day, observed as a holiday on which post-men, errand-boys, and servants of various kinds expect to receive a Christmas-box.
The term Christmas-box, meanwhile, dates back to the seventeenth century, and amongst other things meant
- A present or gratuity given at Christmas: in Great Britain, usually confined to gratuities given to those who are supposed to have a vague claim upon the donor for services rendered to him as one of the general public by whom they are employed and paid, or as a customer of their legal employer; the undefined theory being that as they have done offices for this person, for which he has not directly paid them, some direct acknowledgement is becoming at Christmas.
The European tradition, which has long included giving money and other gifts to those who were needy and in service positions, has been dated to the Middle Ages, but the exact origin is unknown. It is believed to be in reference to the Alms Box placed in places of worship to collect donations to the poor. Also, it may come from a custom in the late Roman/early Christian era, wherein metal boxes placed outside churches were used to collect special offerings tied to the Feast of Saint Stephen, which in the Western Churchfalls on the same day as Boxing Day.
In Britain, it was a custom for tradespeople to collect "Christmas boxes" of money or presents on the first weekday after Christmas as thanks for good service throughout the year. This is mentioned in Samuel Pepys' diary entry for 19 December 1663. This custom is linked to an older English tradition: since they would have to wait on their masters on Christmas Day, the servants of the wealthy were allowed the next day to visit their families. The employers would give each servant a box to take home containing gifts and bonuses, and sometimes leftover food.
Boxing Day is a secular holiday that is traditionally celebrated on 26 December, the day after Christmas Day, which is also St. Stephen's Day, a religious holiday. When 26 December falls on a Sunday, Boxing Day in many Commonwealth countries and former British dominions is moved to 27 December. In the UK, Boxing Day is a bank holiday. If Boxing Day falls on a Saturday, the following Monday is given as a substitute bank holiday. On the occasion when Christmas Day is on a Saturday and the 26 December on the Sunday, the following Monday (27) is the substitute bank holiday for Boxing Day and Tuesday (28) the substitute bank holiday for Christmas Day.
In Ireland – when the island as a whole was part of the United Kingdom – the Bank Holidays Act 1871 established the feast day of St. Stephen as a non-movable public holiday on 26 December. Since the creation of the Republic of Ireland following partition in 1920, Northern Ireland – being part of the United Kingdom – officially reverted to use of the British name 'Boxing Day'.
In Australia, Boxing Day is a federal public holiday. In the Australian state of South Australia, 28 December is a public holiday known as Proclamation Day and Boxing Day is not normally a public holiday. The holiday for Proclamation Day is observed on the first weekday after Christmas Day or the Christmas Day holiday. Nowadays Boxing Day is popular in Australia as the first day of a Test cricket match held at the MCG and the annual Sydney to Hobart yacht race. A Test match is also often held in South Africa starting on Boxing Day.
In New Zealand Boxing Day is a statutory holiday; penalty rates and lieu time are provided to employees who work on the day.
In Canada, Boxing Day is a federal statutory holiday. Government offices, banks and post offices/delivery are closed. In some Canadian provinces, Boxing Day is a statutory holiday that is always celebrated on 26 December. In Canadian provinces where Boxing Day was a statutory holiday, and it falls on a Saturday or Sunday, compensation days are given in the following week.
In the US, Boxing Day is celebrated as a public holiday in some, mainly southern, states: Kansas, Kentucky, North Carolina, South Carolina, Virginia and Texas.Although referred to informally as Boxing Day, officially it is called "Day After Christmas Day".
In the UK, Canada, and some states of Australia, Boxing Day is primarily known as a shopping holiday, much like Black Friday (the day after Thanksgiving) in the US. Boxing Day sales are common in Canada. It is a time where shops have sales, often with dramatic price reductions. For many merchants, Boxing Day has become the day of the year with the greatest amount of returns. In the UK in 2009 it was estimated that up to 12 million shoppers appeared at the sales (a rise of almost 20% compared to 2008, although this was also affected by the fact that the VAT was about to revert to 17.5% from 1 January, following the temporary reduction to 15%).
Many retailers open very early (typically 5 am or even earlier) and offer doorbuster deals and loss leaders to draw people to their stores. It is not uncommon for long queues to form early in the morning of 26 December, hours before the opening of shops holding the big sales, especially at big-box consumer electronics retailers. Many stores have a limited quantity of big draw or deeply discounted items. Because of the shoulder-to-shoulder crowds, many choose to stay home and avoid the hectic shopping experience. The local media often cover the event, mentioning how early the shoppers began queuing up, providing video of shoppers queuing and later leaving with their purchased items. Many retailers have implemented practices aimed at managing large numbers of shoppers. They may limit entrances, restrict the number of patrons in a store at a time, provide tickets to people at the head of the queue to guarantee them a hot ticket item or canvass queued-up shoppers to inform them of inventory limitations.
In recent years, retailers have expanded deals to "Boxing Week". While Boxing Day is 26 December, many retailers will run the sales for several days before or after 26 December, often up to New Year's Eve. Notably, in the recession of late 2008, a record number of retailers were holding early promotions due to a weak economy. Canada's Boxing Day has often been compared with the American Super Saturday, the Saturday before Christmas.
In some areas of Canada, particularly in Atlantic Canada and parts of Northern Ontario, most retailers are prohibited from opening on Boxing Day, either by provincial law or municipal bylaw, or instead by informal agreement among major retailers to provide a day of relaxation following Christmas Day. In these areas, sales otherwise scheduled for 26 December are moved to the 27th. The city council of Greater Sudbury, Ontario, which was the largest city in Canada to maintain this restriction as of the early 2010s, formally repealed its store hours bylaw on December 9, 2014.
In the Republic of Ireland, since 1902, most shops remain closed on St. Stephen's Day. In 2009, some shops opened on this day, breaking a 107-year-old tradition.
In the United Kingdom, it is traditional for the Premier League (England), Scottish Premiership (Scotland) and NIFL Premiership (Northern Ireland), as well as the lower divisions and rugby leagues, to hold a full programme of football and rugby union matches on Boxing Day. Traditionally, matches on Boxing Day are played against local rivals. This was originally to avoid teams and their fans having to travel a long distance to an away game on the day after Christmas Day. It also makes the day an important one in the sporting calendar. In Australia, New Zealand and South Africa, much anticipated cricket Test matches are played on Boxing Day. Prior to the formation of leagues, a number of importantrugby fixtures took place on Boxing Day notably Llanelli v London Welsh and Leicester v The Barbarians.
Boxing Day is one of the main days in the hunting calendar for hunts in the UK and US, with most hunts (both mounted foxhound or harrier packs and foot packs of beagles or bassets) holding meets, often in town or village centres. 
Several ice hockey contests are associated with the day. The IIHF World U20 Championship typically begins on 26 December, while the Spengler Cup also begins on 26 December in Davos, Switzerland; the Spengler Cup competition includes HC Davos,Team Canada, and other top European Hockey teams. The National Hockey League traditionally had close to a full slate of games (10 were played in 2011), following the league-wide days off given for Christmas Eve and Christmas Day. However, the 2013 collective bargaining agreement (which followed a lockout) extended the league mandate of Christmas Eve and Christmas Day off to include Boxing Day, except when it falls on a Saturday, in which case the league can choose to make December 23 a league-wide off day instead for that year. In some African Commonwealth nations, particularly Ghana, Uganda, Malawi, Zambia and Tanzania, prize fighting contests are held on Boxing Day. This practice has also been followed for decades in Guyana and Italy.
A notable tradition in Sweden is Annandagsbandy, which formerly marked the start of the bandy season and always draw large crowds. Matches traditionally begi