The Descriptio Cambriae or Descriptio Kambriae (Description of Wales) is a geographical and ethnographic treatise on Wales and its people dating from 1193 or 1194. The Descriptio’s author, variously known as Gerald of Wales or as Giraldus Cambrensis, was a prominent churchman of Welsh birth and mixed Norman-Welsh ancestry. It is divided into two books, the first concentrating on the virtues of the Welsh people, and the second on their faults.

In the First Preface Gerald justifies his decision to write on the subject of his own country, describing those things around him that have hitherto gone unrecorded, rather than treating of classical subjects which have been better dealt with by others. In the future he plans to write an unspecified magnum opus, but for the time being he will describe Wales, taking the 6th-century writer Gildas for his model. In the Second Preface Gerald praises his dedicatee, and asks him to read the Descriptio. He declares his love of literature, which has inspired him to undertake the hard work needed to research and write such a book. He hopes to be rewarded with the attention and praise of readers, now and in the future.

Book 1 begins with a description of the geographical extent of Wales, and of the country's physical ruggedness. Wales is, says Gerald, divided into the principalities of Gwynedd, Powys and Deheubarth, and has been since the kingdom of Rhodri Mawr was split between his three sons, each of whose descendants down to the present prince are then listed. He then gives the number of cantrefs into which each principality is divided, and names their palaces and dioceses. The course of each of Wales’s principal rivers is described, with a lengthy digression on the habits of the beaver. The author compares the fertility of the various regions of Wales, and the purity of their Welsh, then discusses the etymology of the names Cambria and Wales. He outlines the high military spirit, weapons, armour and tactics of the Welsh, then, turning to their customs in times of peace, describes their frugality, hospitality to strangers, table manners and sleeping habits, and their care of their teeth and facial hair.

A short preface to Book 2 announces Gerald's intention of now describing the Welsh people's worse points. He begins by complaining of their constant perjuries and lack of good faith, then moves on to their propensity towards living by robbery and plunder. In this they show no courage, he says, and goes on to show from historical examples that in the past they have been cowardly or heroic as their circumstances changed. At present they excel at guerrilla warfare, but in a pitched battle they flee if their first attack fails. They are greedy for land, and their princely families are often divided between warring brothers, though foster-brothers are much closer.