The Honourable Society of Cymmrodorion (Welsh: Anrhydeddus Gymdeithas y Cymmrodorion), often called simply the Cymmrodorion, is a London-based Welsh learned society, with membership open to all. It was first established in 1751 as a social, cultural, literary and philanthropic institution. It fell into abeyance between 1787 and 1820, and again between 1843 and 1873. In its second and third incarnations its interests have been predominantly cultural and antiquarian. The present society claims continuity from that founded in 1751, although the three successive societies have in fact been slightly different in character and aims.
The society continues to be based in London, but now draws two-thirds of its membership from Wales.
The Society was founded by the brothers Lewis and Richard Morris, natives of Anglesey. The name, coined by Lewis Morris, was a form of the Welsh: cyn-frodorion ("earliest natives"), in reference to the place of the Welsh as heirs to the ancient Britons.
Several factors combined to prompt the foundation of the new society. One may have been Lewis Morris's disappointment at his failure to be elected a Fellow of the Royal Society. More important was a desire to support the Welsh Charity School, established in 1716 under the auspices of another London Welsh Society, the Honourable and Loyal Society of Antient Britons. By the 1740s the Antient Britons had become somewhat moribund, and the new Society of Cymmrodorion was intended in part to supplement its efforts. It was also to raise funds to relieve impoverished Welsh people in London. The Society's primary object, however, was to be a hub of social activity for the Welsh in London, and (in the absence of a recognised political or cultural "capital" of Wales) a focus of Welsh culture. Regular meetings were held on the first Wednesday of each month, when papers were read on a variety of literary and learned topics.