Gruffudd Fychan (antiquarian spelling: Gruffydd Fychan) could refer to:
Gruffudd Fychan I, Prince of Powys Fadog (reigned 1277–1284) Gruffudd Fychan II (c. 1330–1369), Lord of Glyndyfrdwy and Cynllaith and father of Owain Glyndŵr, Prince of Wales Gruffudd Fychan ap Gruffudd ab Ednyfed (14th century), a Welsh-language poet Gruffudd Vychan (c. 1395–1447), Welsh knight and supporter of Owain Glyndŵr