Laurence Dermott (/ˈdɜːrmət/; 1720 – June 1791) was born in Ireland and became a Freemason in 1741. He held various offices before being installed as Worshipful Master of Lodge No. 26 in Dublin on 24 June 1746. He moved to London in 1748, possibly working as a journeyman painter, and possibly with a view to expanding his father's business. He would later work as a wine merchant, like his father.
He married his first wife, Susanna Neale, a widow, in 1759. She died in 1764. He married his second wife, Mary Windell, also a widow, in 1765 but she died after just three months of marriage in February 1766. Dermott married his third wife Elizabeth Merryman, another widow on 13 November 1766. She had two daughters by her first husband, John Merryman, who had died in 1760. She and Dermott had a son named Laurence after his father in 1767 but he did not survive infancy.
Dermott lived in Aldgate, Mile End and Stepney. He served as Grand Secretary of the Ancient Grand Lodge of England from 1752 to 1771. He wrote and published the Book of Constitutions of this Grand Lodge for the Ancient Grand Lodge of England, which he titled the Ahiman Rezon. Above all, it was Dermott's drive and tenacity that is credited with turning an association of six London lodges in 1751 into a viable and successful Grand Lodge, with lodges throughout England and the colonies.