William Boyde (born 15 December 1994) is a Welsh rugby union player who plays for the Cardiff Blues at flanker, he can also play Number 8. He was a Wales under-20 international. Boyde made his debut for the Scarlets in 2014, whilst also playing for feeder club Carmarthen Quins. Boyde was released from the Scarlets at the end of the 2018-2019 Pro14 season. He was signed by the Cardiff Blues following season, making his competitive debut in a 27-31 win against the Southern Kings.