John of Brittany, 4th Earl of Richmond, was an English nobleman and a member of the Ducal house of Brittany, the House of Dreux. He entered royal service in England under his uncle Edward I, and also served Edward II. On 15 October 1306 he received his father's title of Earl of Richmond. He was named Guardian of Scotland in the midst of England's conflicts with Scotland and in 1311 Lord Ordainer during the baronial rebellion against Edward II.

The now-extinct title of Earl of Richmond was created many times in the Peerage of England. The earldom of Richmond was initially held by various Breton nobles; sometimes the holder was the Breton duke himself, including one member of the cadet branch of the French Capetian dynasty. The historical ties between the Duchy of Brittany and this English earldom were maintained ceremonially by the Breton dukes even after England ceased to recognize the Breton dukes as earls of England and those dukes rendered homage to the King of France, rather than the English crown. It was then held either by members of the English royal families of Plantagenet and Tudor, or English nobles closely associated with the English crown. It was eventually merged into the English crown during the reign of Henry VII of England and has been recreated as a Dukedom.