The U.S. government estimates the total population at 57 million (midyear 2021).  According to a 2010 Pew Research Center report, 81 percent of the population is Christian.  Approximately 15 percent of the population adheres to no particular religion or declined to indicate an affiliation; some of these individuals likely adhere to indigenous beliefs.  Muslims constitute 1.7 percent of the population, of whom the great majority are Sunni.  Shia religious leaders estimate that not more than 3 percent of the Muslim population is Shia.  Hindus, Jews, Buddhists, and adherents of traditional indigenous beliefs together constitute less than 4 percent of the population.  Many indigenous persons adhere to a belief system combining Christian and indigenous religious practices.  The Church of Scientology estimates it has approximately 100,000 members.

The Pew Research Center estimates 84 percent of the Christian population is Protestant, 11 percent Roman Catholic, and 5 percent other denominations (as of 2010, the latest figures available).  African Independent Churches constitute the largest group of Christian churches, including the Zion Christian Church (approximately 11 percent of the population), the Apostolic Church (approximately 10 percent), and charismatic groups.  Other Christian groups include Methodists, Anglicans, Baptists, Lutherans, Presbyterians, Seventh-day Adventists, and members of the Greek Orthodox, Dutch Reformed, The Church of Jesus Christ of Latter-day Saints, Assemblies of God, and Congregational Churches.

Persons of Indian or other Asian heritage account for 2.5 percent of the total population.  Approximately half of the ethnic Indian population is Hindu, and the majority reside in KwaZulu-Natal Province.  The Muslim community includes Cape Malays of Malayan-Indonesian descent, individuals of Indian or Pakistani descent, and approximately 70,000 Somali nationals and refugees.

According to a 2020 study published by the Isaac and Jessie Kaplan Centre for Jewish Studies at the University of Cape Town and the UK-based Institute for Jewish Policy Research, the country’s Jewish population stands at 52,300, with the majority living in Cape Town and Johannesburg.  The study found that the Jewish population declined over the past 20 years primarily because of emigration.