Both the United States and Australia have multipillar retirement systems that include a public component and a private component. Increasingly, the private component consists of a defined contribution plan. At the outset, this Article provides an overview of the retirement systems of the United States and Australia. Next, this Article compares the rules governing defined contribution plans in the United States and Australia. In particular, this Article focuses on the rules governing the contribution, accumulation, and distribution stages; and it discusses which public policies will best help workers maximize their defined contribution plan accumulations and, consequently, the retirement income that they will eventually receive. Ultimately, this Article develops recommendations for the optimal rules for defined contribution plans in the United States, Australia, and around the world.