Abstract
The work aims to analyze the principles of primogeniture rule and its position under international human rights law; studying cases in Nigeria, South Africa and United Kingdom. The research used a qualitative research design method which is deemed the ideal design to use within the qualitative methodology because of its ability to facilitate exploration of the phenomenon within its context, using a variety of secondary data. The study collected and analyzed non-numerical data (e.g., text, and video) which are all secondary. It is obvious that the primogeniture system has a negative standing in international human rights legislation. The study discovered that primogeniture rule is still significant and applicable in Nigeria, where it is recognized and applied. Customary law and statutes both directly and indirectly support its application. The work suggests a legal framework to be established to handle any failure to uphold the obligation of assistance and care.