The Glasites /ˈɡlæsaɪts/ or Glassites were a small Christian church founded in about 1730 in Scotland by John Glas. Glas's faith, as part of the First Great Awakening, was spread by his son-in-law Robert Sandeman into England and America, where the members were called Sandemanians.

Glas dissented from the Westminster Confession only in his views as to the spiritual nature of the church and the functions of the civil magistrate. But Sandeman added a distinctive doctrine as to the nature of faith which is thus stated on his tombstone:

In a series of letters to James Hervey, the author of Theron and Aspasio, Sandeman maintained that justifying faith is a simple assent to the divine testimony concerning Jesus, differing in no way in its character from belief in any ordinary testimony.

In their practice the Glasite churches aimed at a strict conformity with the primitive type of Christianity, as understood by them. Each congregation had a plurality of elders, pastors, or bishops, who were chosen according to what were believed to be the instructions of Paul, without regard to previous education or present occupation, and who enjoy a perfect equality in office. To have been married a second time disqualified one for ordination, or for continued tenure of the office of bishop.

In all the action of the church unanimity was considered to be necessary; if any member differed in opinion from the rest, he must either surrender his judgement to that of the church, or be shut out from its communion. To join in prayer with anyone not a member of the denomination was regarded as unlawful, and even to eat or drink with one who had been excommunicated was held to be wrong. The Lord's Supper was observed weekly; and between forenoon and afternoon service every Sunday a love feast was held at which every member was required to be present. This took the form not of symbolic morsels of wine and bread, as in other communions, but a (relatively) substantial meal, a custom leading to the Glasites' nickname of "Kail Kirk" for the Scotch broth that was served at this setting. This custom may have arisen, in part, as a charitable response to the poverty of most members of this Church and also as a pragmatic response to the length of meetings (particularly the sermons) and the distances some members of the congregation had to travel in order to attend.

At Glasite services, any member who "possesses the gift of edifying the brethren", was allowed to speak. The practice of washing one another's feet was at one time observed; and it was for a long time customary for each brother and sister to receive new members, on admission, with a holy kiss.

"Things strangled and blood" were rigorously abstained from. They disapproved of all lotteries and games of chance. The accumulation of wealth they held to be unscriptural and improper.

A church was set up by Glas in Dundee following his suspension by the Church of Scotland, with its congregation becoming known as Glasites. The first meeting house in Perth followed in 1733. Glasite churches were also founded in Paisley, Glasgow, Edinburgh, Leith, Arbroath, Montrose, Aberdeen, Dunkeld, Cupar, and Galashiels. Buildings built as Glasite chapels survive in Dundee, Edinburgh and Perth (two), Galashiels and possibly elsewhere.