William Ellis Gloag, Lord Kincairney (7 February 1828 – 8 October 1909) was a Scottish judge.

Paton James Gloag the theologian writer and Moderator of the General Assembly of the Church of Scotland in 1889, was his eldest brother, and his eldest sister was Jessie Burn Gloag, who founded a ragged school in Perth.

A Conservative in politics, he was not offered promotion until 1874, when he was appointed advocate depute on the formation of Disraeli's second ministry.

In later life he owned a large Georgian townhouse at 6 Heriot Row, Edinburgh which had previously been the home of the author Henry Mackenzie.

[3] In 1864, Gloag married Helen, daughter of James Burn, Writer to the Signet.