The differing views that various parties and states hold regarding the efficacy of their Islamisation approach and its impact nationally remain unresolved until today. This paper is an attempt to assess the well-being of countries in an objective and scientific manner. It introduces a new Islamic Index of Well-being (IIW) for Muslim Majority Countries (MMCs), which is based on principles derived from the Qur’an and Sunnah to comprise the key fields of Personal Religiosity and Social Interactions. These two elements are given equal weighting. The Religiosity element is obtained from published data of the Pew Research Center for indicators of the percentage of Muslim citizens who perform obligatory practices of praying five times daily, men attending the mosque at least once weekly, and Muslims fasting in Ramadan (or paying zakah). Research has shown a direct, positive relationship between Religiosity levels and psychological well-being. Five parameters are assessed for the Social Interactions performance of MMCs: secondary education, good status of women, care of children, limited income inequality and elimination of corruption. From an Islamic perspective, governments are required to assist weaker members of society, which is reflected in indicators used to determine the status of women, children and the poor. The resultant IIWs calculated for the 27 (Arab Gulf countries were not surveyed) out of a total 50 MMCs plus Nigeria show that the highest IIW levels are in Southeast Asia (Malaysia and Indonesia take the top positions), followed by Senegal and the Palestinian Territories. Middle Eastern countries follow, then sub-Saharan African countries with overlap, while former Communist bloc countries generally have the lowest indices. 2012 IIWs represent a base level for the measurement of country improvements in years to come.