The Quadrilateral Security Dialogue is also referred to as the QSD or the Quad. It is a strategic security dialogue that exists between the United States, Australia, Japan, and India. It is maintained by talks between these four countries.

The dialogue was first initiated in 2007. Joint military exercises also took place at this time. Exercises of this scale had never occurred before and it became known as Exercise Malabar.

The following year, Kevin Rudd became Prime Minister of Australia and withdrew from the agreement. This was in part due to the fact that Australia did not want to get caught up in any conflict between China and the United States. The partnership as it stood was ended.

By 2010, Julia Gillard was the Australian Prime Minister and military cooperation between the country and the United States was resumed. Several years later, the dialogue between the four countries was opened up again.