Iestyn

Iestyn is a masculine given name, the Welsh equivalent of English Justin, and may refer to:

• Iestyn (saint), Welsh saint of the 6th or 7th centuries
• Iestyn Davies, British opera singer
• Iestyn ap Gwrgant (1045–1093), the last ruler of the Welsh kingdom of Morgannwg
• Iestyn Edwards, stage and TV writer/performer, published poet and journalist
• Iestyn Harris (born 1976), Welsh professional rugby league footballer
• Iestyn Thomas (born 1976), Welsh rugby union footballer
• Rhydderch ap Iestyn (died 1033), king of Gwent and Morgannwg in south Wales