Participants are encouraged to wear a t-shirt representing their favourite local artist, and make a donation to music industry charity Support Act.
The initiative raises hundreds of thousands of dollars every year through the sales of limited edition t-shirts, often sold at community markets across the country.
From 2007, British DJ Steve Lamacq annually championed Wear Your Old Band T-Shirt to Work Day, an initiative he created as host of BBC Radio 6 Music.
Inspired by this, Ollie Wards, content director of Australian youth radio station Triple J, began a social media trend in 2013 with the hashtag #AusBandTShirtDay.
[4] The 2024 campaign saw Support Act launch Mobmusic T-Shirt Day, a fundraiser specifically promoting Aboriginal Australian and Torres Strait Islander musicians.