Alpha was started by the Reverend Charles Marnham, a curate at Holy Trinity, Brompton, a Church of England parish in London. The name 'Alpha' was suggested by Marnham's wife, Tricia. It started as a course for church members on the basics of the Christian faith but then began to be used as an introduction for those interested in the faith. The Very Reverend John Irvine, at that time a curate at HTB, took over running the course and developed it into the ten week format which continues to this day. In 1990 the Reverend Nicky Gumbel, at that time a curate at Holy Trinity, took over the running of the course at the invitation of the Reverend Sandy Millar (the then vicar) and oversaw its revision and expansion.

In 2008 over 33,500 courses were offered in 163 countries by Anglican, Presbyterian, Lutheran, Baptist, Methodist, Pentecostal, British Church New Movement and Orthodox  churches and the Roman Catholic Church[citation needed]. Over 15 million people worldwide have attended an Alpha course (two and a half million in the UK).