Happiness is a feeling that is desired by every human being. To achieve happiness, human try various routes like, to gain financial superiority, fame, entertainment, assets and so on. But on the contrary, religiosity is claimed to be a technique to attain purpose in life, mental health, physical well-being and internal peace, which ultimately leads to happiness in life. This study analyses the studies conducted in last two decades toward understanding the relationship between religiousness and happiness. These studies have been organised in terms of the religions, geographic locations, scales and significance. The study shows that the claim has proven to be true by a vast majority of the surveys irrespective of religion, gender, nationality or race. Although Muslims seems to be the happiest, it requires further verification.