Baháʼí Faith by country

The Baháʼí Faith formed in the late 19th century in the Middle East, later gaining converts in India, East Africa, and the Western world. Traveling promoters of the religion played a significant role in spreading the religion into most countries and territories during the second half of the 20th century, mostly seeded out of North America by means of the planned migration of individuals. The Baháʼí Faith was recognized as having a widespread international membership by the 1980s, and is now recognized as the second-most geographically widespread religion after Christianity.

The Baháʼí World Centre estimated over a million Bahá'ís in 1965, 5 million in 1991, and about 8 million in 2020. The official agencies of the religion have focused on publishing data such as numbers of local and national spiritual assemblies, countries and territories represented, languages and tribes represented, schools, and publishing trusts, not the total number of believers.

Analyzing Baháʼí data on localities and activity levels, Danish sociologist Margit Warburg suggested that by 2001 registered Baháʼís reliably numbered over 5 million, and that active participants numbered approximately 900,000 (18% of registered Baháʼís). Independent estimates, such as Encyclopædia Britannica and the World Christian Encyclopedia, have listed Baháʼí membership as over 7 million, and described it as the fastest growing religion by percentage across the 20th century.

The number of adherents of a religion spread across many countries is exceptionally difficult to estimate accurately. Few national Baháʼí communities have the administrative capacity for efficient enumeration of membership, and Baháʼí membership data does not break out active participation from the total number of people who have expressed their belief. Due to its small size, few censuses or religious surveys include the Baháʼí Faith as a separate category, and some government censuses count Baháʼís as Muslims or Hindus. Country-level detail from World Christian Encyclopedia (WCE), on which many other estimates rely, attempts to count declared Baháʼís along with sympathizers, so its numbers have been consistently much higher than those of self-identifying Baháʼís.