Consensual sexual activity between adults of the same sex is criminalised in Nigeria. This stems from prevailing socio-cultural and religious beliefs that portray same-sex sexual relationships as unnatural, un- African, and morally reprehensible. Religious people would go further to regard it as demonic. It is on this basis that the Same Sex Marriage (Prohibition) Act (SSMPA) 2013, which criminalises various forms of same- sex unions and public display of same-sex amorous relationships, was enacted by the Nigerian government. This legislation was birthed notwithstanding that the Constitution of the Federal Republic of Nigeria, 1999 (as amended) guarantees the fundamental rights of all citizens, irrespective of one’s sexual orientation. These rights include the right to life, freedom from discrimination, right to personal liberty, right to freedom of assembly and association, right to fair hearing, and right to privacy. The study adopts a doctrinal research methodology to analyse the constitutionality of the SSMPA with regards to its alignment or otherwise with the fundamental rights enshrined in Chapter IV of the 1999 Constitution (as amended), particularly the right to privacy, right to freedom of assembly and association, and right to freedom from discrimination. The study contributes to the scholarly debate on LGBTQ+ rights and argues for the protection of the fundamental rights of every individual, regardless of gender identity and sexual oreintation.