The Shop Distributive and Allied Employees Association (SDA) is the largest trade union in Australia with more than 230,000 members and branches in every state and one in the Newcastle, Hunter Valley and Central Coast region. The SDA is associated with the right wing of the union movement and the Australian Labor Party. It uses the services model of the trade union.

The main types of workers covered by the SDA are retail shop assistants and fast food workers but the SDA covers a much more diverse range from hairdressers to butchers. The current national secretary is Joe de Bruyn.