Christians ( (listen)) are people who follow or adhere to Christianity, a monotheistic Abrahamic religion based on the life and teachings of Jesus Christ. The words Christ and Christian derive from the Koine Greek title Christós (Χριστός), a translation of the Biblical Hebrew term mashiach (מָשִׁיחַ) (usually rendered as messiah in English). While there are diverse interpretations of Christianity which sometimes conflict, they are united in believing that Jesus has a unique significance. The term Christian used as an adjective is descriptive of anything associated with Christianity or Christian churches, or in a proverbial sense "all that is noble, and good, and Christ-like." It does not have a meaning of 'of Christ' or 'related or pertaining to Christ'.

According to a 2011 Pew Research Center survey, there were 2.2 billion Christians around the world in 2010, up from about 600 million in 1910. Today, about 37% of all Christians live in the Americas, about 26% live in Europe, 24% live in sub-Saharan Africa, about 13% live in Asia and the Pacific, and 1% live in the Middle East and North Africa. Christians make up the majority of the population in 158 countries and territories. 280 million Christians live as a minority. About half of all Christians worldwide are Catholic, while more than a third are Protestant (37%). Orthodox communions comprise 12% of the world's Christians. Other Christian groups make up the remainder. By 2050, the Christian population is expected to exceed 3 billion. According to a 2012 Pew Research Center survey, Christianity will remain the world's largest religion in 2050, if current trends continue. In recent history, Christians have experienced persecution of varying severity, especially in the Middle-East, North Africa, East Asia, and South Asia.