Robert of Rhuddlan (died 3 July 1093) was a Norman adventurer who became lord of much of north-east Wales and for a period lord of all North Wales. Robert was the cousin of Hugh d'Avranches, 1st Earl of Chester, and appears to have come to the Welsh Marches before 1066 in the service of Edward the Confessor. Hugh became Earl of Chester in 1070, and Robert appears to have been appointed Hugh's "commander of troops" in 1072. He immediately began hostilities with the Welsh, and having captured land in the cantref of Tegeingl (North East Wales) he built a Motte-and-bailey castle at Twthill near Rhuddlan, holding the lands as a vassal of Earl Hugh.