Find ITAT Lawyers in Chennai. What is Income Tax Appellate Tribunal (ITAT)? It is a quasi-judicial authority to file appeals against the orders of income tax authorities. A tax appeal can be filed by a taxpayer who does not agree with the assessment order or any other order, passed by an income-tax authority. Similarly, an income-tax authority can also file an appeal against any order passed by lower income-tax authorities. Act establishing the Tribunal: The Income-tax Act, 1961. The Appellate Court for ITAT is High Court. Contact Top ITAT Attorneys in India.