| Billy Guyton | |
| Birth Name: | Billy-John Guyton |
| Birth Date: | 1990 3, df=yes |
| Birth Place: | Timaru, New Zealand |
| Death Place: | Nelson, New Zealand |
| Height: | 1.86 m |
| Weight: | 900NaN0 |
| Ru Position: | Halfback First five-eighth |
| Repteam1: | Māori All Blacks |
| Repyears1: | 2016 |
| Repcaps1: | 0 |
| Reppoints1: | 0 |
| Super1: | Hurricanes |
| Super2: | Crusaders |
| Superyears1: | 2014 |
| Superyears2: | 2015 |
| Superyears3: | 2016−2017 |
| Superapps1: | 1 |
| Superapps2: | 1 |
| Superapps3: | 24 |
| Superpoints1: | 0 |
| Superpoints2: | 0 |
| Superpoints3: | 10 |
| Super14update: | 20 July 2016 |
| Province1: | North Otago |
| Province2: | Tasman |
| Provinceyears1: | 2010–2012 |
| Provinceyears2: | 2013–2017 |
| Provinceapps1: | 29 |
| Provinceapps2: | 52 |
| Provincepoints1: | 89 |
| Provincepoints2: | 90 |
| Ru Provinceupdate: | 23 September 2018 |
| School: | Shirley Boys' High School Nelson College |
Billy-John Guyton (17 March 1990 – 15 May 2023) was a New Zealand rugby union player. He played at halfback for provincial side Tasman.[1] Guyton spent the previous three years playing for North Otago in the Heartland championship, making 29 appearances for the province. He then moved north to sign with the Tasman Mako ahead of 2013 season's ITM Cup.
2013 saw Guyton establish himself as the starting halfback for Tasman as they went on to have a successful season and win the champion division in the ITM Cup, with a one-point win over Hawke's Bay 26–25. This saw Tasman Mako promoted to the Premiership Division of the ITM Cup.
A strong season for the Tasman Mako saw Guyton sign with the Hurricanes for the 2014 super rugby season.
The 2014 super rugby season saw Guyton get very little game time for the Hurricanes. This saw Guyton initially released for the 2015 season, but a season-ending injury to Willi Heinz saw the Crusaders sign him as a replacement for the remainder of the 2015 super rugby season.[2]
After another season of little action as a member of the Crusaders, Guyton signed a contract with the,[3] his 3rd super rugby team in as many years.
In October 2016 Guyton, who affiliated with the Ngāpuhi, Ngāti Pikiao, and Ngāti Raukawa iwi, was named in the Māori All Blacks team for their end-of-year tour to the Northern Hemisphere.[4]
Guyton also played for the New Zealand Heartland XV at fullback and wing.
Guyton announced his retirement from playing rugby in October 2018, aged 28, after repeated concussions suffered in official matches had left him with symptoms of chronic traumatic encephalopathy (CTE).[5] [6]
He died in Nelson on 15 May 2023, at the age of 33.[7] Subsequent reports in New Zealand media said Guyton was suspected to have died by suicide.[8]
Guyton's family decided to donate his brain to the Neurological Foundation Human Brain Bank at the University of Auckland; following post-mortem analyses conducted in New Zealand and Australia, he was diagnosed with stage 2 CTE in March 2024, becoming the first New Zealand-based player to be officially diagnosed with the disease. The pathologist's report also found that Guyton's brain presented trauma-induced cavum septum pellucidum, as well as age-related tau deposits.