Owain Lawgoch (Owain of the Red Hand), full name Owain ap Thomas ap Rhodri (c. 1330 - July 1378), was a Welsh soldier who served in Lombardy, France, Alsace, and Switzerland. He led a Free Company fighting for the French against the English in the Hundred Years' War. As a politically active descendant of Llywelyn the Great in the male line, he was a claimant to the title of Prince of Gwynedd and of Wales.

Lawgoch was a lineal direct descendant of the Welsh Prince Llywelyn the Great, through his illegitimate son Gruffudd (d. 1244). His grandfather was a member of the Welsh Royal House of Gwynedd, and Owain was very aware of his dynastic hereditary claim as the last living male of Llywelyn's family. Following the death of Prince Llywelyn the Last in 1282 and the execution of his brother and successor as the final Prince of Gwynedd Dafydd ap Gruffudd in 1283, the Welsh kingdom paid fealty to and accepted English rule. Llywelyn's daughter Gwenllian ferch Llywelyn was committed to a nunnery at Sempringham, while the sons of Dafydd were kept in Bristol Castle until their deaths. Another of Llywelyn's brothers, Rhodri ap Gruffydd, renounced his rights in Gwynedd and spent much of his life in England as a royal pensioner. His son Thomas inherited lands in England in Surrey, Cheshire and Gloucestershire.

Rhodri was content to end his life as a country gentleman in England, and though his son Thomas ap Rhodri used the four lions of Gwynedd on his seal he made no attempt to win his inheritance. Owain, his only son, was born in Surrey, where his grandfather had acquired the manor of Tatsfield. Lawgoch entered the military service of Philip IV of France and lived the majority of his life on in mainland Europe. Thomas died in 1363 and Owain returned from abroad to Montgomeryshire and proclaimed his patrimony as the Prince of Wales. He was also in Britain during 1365. Lawgoch left again for France in March 1366 and was in French service by 1369 (hostilities in the war were suspended between 1360 and 1369), but adhering to the enemy had his lands in Wales and England confiscated.