Christianity is the most popular religion in the world. Combining all of its denomination, Christianity has 2. 1 billion adherents. There are 1. 3 billion Muslims, 860 million Hindus, 380 million Buddhists and 25 million Sikhs.
The five religions that have the most adherents worldwide are: Christianity, Islam, Judaism, Hinduism and Buddhism. All have several sects within them.
Here are their order in number of believers: Christianity, Islam, Hinduism, Buddhism and finally Sikhism. One would think that Judaism comes before Sikhism, but it comes in sixth place.