Moomba (also known as the Moomba Festival) is held annually in Melbourne, Australia. Run by the City of Melbourne, it is Australia's largest free community festival.^[1] The Melburnian tradition is celebrated over four days, incorporating the Labour Day long weekend, from Friday to the second Monday in March. Moomba is culturally important to Melbourne, having been celebrated since 1955, and regularly attracts up to a million people, with a record attendance of 3.8 million (2.3 million tourists) set in 2018.^{[citation needed]}

In 2003, the event was renamed Melbourne Moomba Waterfest.

Traditional events include the Moomba parade, crowning of Moomba monarchs, fireworks displays, carnivals in the gardens along the river, river activities including watersports, water floats and the Birdman Rally, as well as live music and bands.

In 2021, the usual Moomba was cancelled by Melbourne City Council, for the first time ever, due to events and issues related to the COVID-19 pandemic in Australia. However "Moomba 2.0" events were held on 5–8 March. In 2024 a forecast of extremely hot weather caused the Moomba Parade to be cancelled.

In 1951, Australia celebrated fifty years of Federation with a parade and the staging of the theatre production An Aboriginal Moomba: Out of the Dark. In 1954, Queen Elizabeth II visited the city for the first time as reigning monarch, and the City Development Association and the Melbourne City Council proposed an autumn carnival to be known as "Moomba".^[2] A committee was formed in July, 1954 to organise and fund the event, successfully allocating £10,000 to its inaugural running. Before the event's first year, controversy was created when Labor Councillor Frank Williams resigned from the committee, branding the planned carnival as a "Bourke street joke for the benefit of shopkeepers".^[3] A promotional theme song "Come to Melbourne for the Moomba" was written by Jack O'Hagan.

The festival was originally named Moomba by organisers in the belief it was a native word meaning 'let's get together and have fun.' Credit is usually given to Bill Onus, a unionist and member of the Australian Aborigines' League for proposing the term, which he used in a play, Aboriginal Moomba in 1951.^[4] In 1969 Luise Hercus glossed the word mum (rhyming with 'vroom')^[5] as meaning 'bottom, rump', and suggested mum-ba meant something like 'bottom and..', and had been introduced from Healesville usage as a joke.^[6] In 1981 Barry Blake analysed the word as combining as mum (anus) and –ba, a locative suffix meaning 'at, in, on'. This would give the sense of 'up your bum/arse'.^[7][8]

Onus himself, according to his daughter-in-law, who said she had heard the story from Onus's wife Mary, had picked up the word from a word list of indigenous terms.^[4] Some say he did it to get back at the city council for having deliberately upstaged the traditional Labour Day march with a popular carnival. Lin Onus, his son, stated that indeed his father had intended to play a prank in passing on the word with this sense.^[5]

The first Moomba was a 15-day festival officially opened on 12 March 1955 by the State Governor, Sir Dallas Brooks.^[9] The inaugural programme included a fireworks display, parade, vintage car display, Henley rowing regatta, river floats including a "Lord Mayor's houseboat", cycling race, tennis at Kooyong, concerts including performances by the Victorian Symphony Orchestra and Royal Philharmonic choir, crowning of the Queen of Moomba and riverside carnival. 25,000 turned out to watch the inaugural Moomba parade down Swanston Street. The first Moomba was heavily criticised by Melbourne's conservative establishment, including the Anglican Church, which at the time claimed it was hedonistic and embodying social decay.^[10] Council responded to the criticism citing that Moomba was intended to be a festival for families and as such is reinforcing family values in society.^[11]

One of the popular events associated with Moomba was the Herald Sun Outdoor Art Show in the Treasury Gardens.^[12][13]

After the 2016 Moomba festival fireworks there was a large-scale brawl in and around Federation Square in Melbourne's Central Business District, largely between members of two gangs, Apex and Islander 23.^[14][15]