The Ranters were one of a number of dissenting groups that emerged about the time of the Commonwealth of England (1649–1660). They were largely common people, and the movement was widespread throughout England, though they were not organised and had no leader.^{[citation needed]}

The chaos of the Second English Civil War, the execution of King Charles I, and the animosity between the Presbyterians and Independents during the era of the Commonwealth gave rise to many sectarian groups that attempted to make sense of their society and place within that society. The Ranters were one such group. They were regarded as heretical by the established Church and seem to have been regarded by the government as a threat to social order. The quote "...the bishops, Charles and the Lords have had their turn, overturn, so your turn shall be next...", published in a Ranter pamphlet, no doubt caused some concern in the halls of power. The Ranters denied the authority of churches, of Scripture, of the current ministry and of services, instead calling on men to listen to the divine within them. In many ways they resemble the 14th century Brethren of the Free Spirit. In fact, they were causing such controversy, that by the early 1650s multiple anti-Ranter pamphlets were circulating throughout Britain.

The origin for the term "Ranter" seems to come from an anonymous pamphlet titled "A Justification of the Mad Crew", where the word rant was used in reference to the enemies of those espousing this particular view, equating ranting with hypocrisy. The anonymous author calls those who would eventually be deemed Ranters "the Mad Crew" instead. There is also a confluence between the term "Ranter" with the verb rent, as in to be rent away from God. Most written evidence points to the use of "Ranter" as an insult by the enemies of the sect and not a self-designated moniker. By the 1660s, the term became attached to any group that promoted theological deviance but since most of the literary evidence we have was created by those opposed to Ranters in general, it is difficult to determine their exact creed.

There are few primary sources actually written by Ranters, but those that do exist give us a clearer picture of what they believed. The most famous English member, Laurence Clarkson or Claxton, joined the Ranters after encountering them in 1649. Although he does not mention them directly, his 1650 tract called A Single Eye is widely believed to have been inspired by this dissenting group and directly reflects their views. Other less well known members of the Ranter cohort included Abiezer Coppe and Joseph Salmon.

Their central idea was pantheistic, that God is essentially in every creature, including themselves.

"If God be in all things, then in all creatures that hath live whatsoever, so that wherein is man better than these, or hath any pre-eminence above these?"

— Laurence Clarkson, A Single Eye (1650).

"My most excellent Majesty (in me) hath strangely and variously transformed this form. And behold, by mine own Almightiness (in me) I have been changed in a moment, in the twinkling of an eye, at the sound of the trump."