Thomas Louth, or de Luda (died after 1338) was an English-born judge who spent much of his career in Ireland. He was notable for his long and ultimately unsuccessful struggle with Elias de Asshebournham for the office of Lord Chief Justice of Ireland.
He was a native of Louth, Lincolnshire, and was sometimes known by the Latin version of his name, Thomas de Luda. In 1324 he appears on a commission of oyer and terminer and in the same year he was appointed a judge of the Court of Common Pleas (Ireland) but did not take up the latter office.
In 1331 he was appointed Lord Chief Justice of Ireland; he moved to Ireland and was granted lands at Howth. He then began a struggle with the Dublin- born judge Elias de Asshebournham to retain the office; the struggle lasted most of the decade, and each replaced the other so often that it is difficult to determine which man held office at any given time. There was a genuine concern on the part of the English Crown about the poor quality of Irish- born judges, so Louth as an Englishman should have had the advantage; but Assehbournham also had influence at Court. In 1337 Louth suffered what seemed to be a decisive defeat when he was imprisoned for unspecified "excesses", yet the following year he was restored to office after "laudable testimony" to his good conduct, only to be finally removed from office later the same year.