Challenging ATO Decisions: Tax Objections & Appeal Process in Australia If you disagree with an Australian Taxation Office (ATO) decision—whether it’s an assessment, penalty or disallowance—you have the right to object and, if necessary, appeal. Follow these five steps to protect your rights and seek a fair outcome. 1. Review the ATO Notice & Identify Grounds Carefully read the ATO’s notice of assessment or penalty. Note the deadline to object (usually 60 days) and identify valid grounds—errors of fact, incorrect application of law or procedural unfairness. 2. Lodge a Formal Objection Submit your objection in writing via ATO Online Services or by mail. Include: Reference to the relevant notice or decision Clear statement of why you disagree Supporting documents (financials, legal submissions) 3. Internal Review & Negotiation The ATO will allocate your objection to a review team. They may contact you for further information or invite you to a conference. ...