If you don’t lodge a tax return when required, you could face several consequences. If you earn above the tax-free threshold of $18,200, you must lodge a return annually. Failure to do so can result in ATO penalties, including a Failure to Lodge (FTL) penalty, which accrues at $330 per 28 days overdue, up to a maximum of five penalty units. If your return remains outstanding, the ATO may issue default assessments based on estimated income, which can lead to higher tax liabilities. In severe cases, prosecution could result in fines or imprisonment for up to 12 months. To avoid these issues, ensure you lodge your returns promptly or seek assistance from a tax accountant to address any overdue returns and potential penalties.