The Citizenship (Amendment) Act, 2019 (CAA) has elicited great controversies and protests by excluding illegal migrants from the benefit of expedited citizenship naturalization in India on religious classification. While the CAA has been challenged as violative of the fundamental rights of equality and non-discrimination, scholarship has neglected situating and examining the legislation’s constitutional validity on the appraisal of the application of the basic structure doctrine. This article addresses that gap by examining whether the basic structure doctrine applies to ordinary legislation like the CAA. It argues that while its applicability is not straightforward, a doctrinal analysis reveals plausible violations of core constitutional principles, including secularism, equality, and the rule of law. The article concludes that if the basic structure doctrine is invoked by the Supreme Court of India to assess the CAA’s constitutional validity, there are compelling grounds to determine that it is unconstitutional, with significant implications for ongoing constitutional litigation.