The Philadelphians were a Protestant 17th century religious sect in England. They were organized around John Pordage (1607 - 1681), a priest in Broadfield, Berkshire, who had been ejected from his parish in 1655 and then reinstated in 1660. Pordage was attracted to the ideas of Jakob Boehme, the Lutheran theosophist.

A group of followers came to Pordage, led by Mrs. Jane Leade (1623 - 1704), who experienced a number of visions and recorded them in A Fountain of Gardens. The group incorporated as The Philadelphia Society for the Advancement of Piety and Divine Philosophy in 1670. They rejected the idea of being a church, and none of the members ceased their memberships in existing churches. Together, the group held views that were somewhat transcendentalist and somewhat pantheist, but with a gnostic component, in that they maintained that their souls were illuminated by the Holy Spirit.

Mrs. Leade's visions were a central part of the sect. The group's views were spread to continental Europe by Francis Lee, a non-juoror at the accession of William III. The group drew up a formal confession of beliefs in 1703. However, after the death of Mrs. Leade, the group's numbers dwindled quickly.