Zachary Macaulay was a Scottish statistician and abolitionist who was a founder of London University and of the Society for the Suppression of Vice, and a Governor of British Sierra Leone.

The Macaulay family of Uig in Lewis, known in Scottish Gaelic as Clann mhic Amhlaigh, were a small family located around Uig on the Isle of Lewis in the Outer Hebrides of Scotland. There is no connection between the Macaulays of Lewis and Clan MacAulay which was centred in the Loch Lomond area, bordering the Scottish Highlands and Scottish Lowlands. The Macaulays of Lewis are generally said to be of Norse origin because of the etymology of their surname and also because of the islands' Viking Age past. However, a recent analysis of the Y-DNA of men with Scottish surnames has shown that a large number of Hebridean Macaulays are of Irish origin. In the 17th century, however, tradition gave the Macaulays an Irish origin. By the end of the 16th century the dominant clan on Lewis was Clan Macleod of The Lewes. Other notable Lewis clans were the somewhat smaller Morrisons of Ness and the even less numerous Macaulays of Uig. The Macaulays were centred in the area surrounding Uig on the western coast of Lewis, and had a deadly, long-standing feud with the Morrisons, whose lands were located on the northern coast around Ness. Today the Lewis surname Macaulay is considered to be a sept name of the Macleods of Lewis. There are two other nearby clans of Macaulays who may, or may not, be connected to the Lewis clan—the Wester Ross Macaulays, and the Uist MacAulays.