| Guillermo Arenas Milán | |
| Position: | Head coach |
| Team: | Alimerka Oviedo Baloncesto |
| League: | LEB Oro |
| Nationality: | Spanish |
| Birth Date: | 1977 12, mf=yes |
| Birth Place: | Oviedo, Asturias |
| Career Position: | Point Guard |
| Coach Start: | 2009–2015, 2016 |
| Cyears1: | 2009–2012 |
| Cteam1: | Universidad de Oviedo (women's) (assistant) |
| Cyears2: | 2009–2010 |
| Cteam2: | Oviedo (reserve team) |
| Cyears3: | 2010–2012 |
| Cteam3: | Oviedo (assistant) |
| Cyears4: | 2012–2015 |
| Cteam4: | Oviedo |
| Cyears5: | 2016–2017 |
| Cteam5: | Baloncesto Villa de Mieres 2012 |
| Highlights: |
|
| Cteam6: | Peñas Huesca |
| Cyears6: | 2017–2020 |
| Team1: | Colegio École |
| Years1: | 2000–2001 |
| Team2: | Asociación Atlética Avilesina |
| Years2: | 2003–2004 |
| Team3: | Oviedo |
| Years3: | 2006–2009 |
| Years4: | 2015–2016 |
| Team4: | Club Baloncesto Castrillón |
| Cteam8: | Círculo Gijón (assistant) |
| Cyears8: | 2021–2022 |
| Cteam9: | Club Ourense Baloncesto |
| Cyears9: | 2022–2023 |
| Cteam10: | Oviedo |
| Cyears10: | 2023– |
Guillermo Arenas Milán is a Spanish basketball coach. Currently he is the Head Coach for Alimerka Oviedo Baloncesto (LEB Oro).
He began his coaching stint with Unión Financiera Asturiana Oviedo Baloncesto back in 2011, serving as the assistant head coach for the team. After a year, in 2012, after spending his first season as assistant coach for the Unión Financiera Asturiana Oviedo Baloncesto, he was duly promoted to be the head coach of the team.
On 2017, he signed with the team, Levitec Huesca.[1] But in May 2020, he left the said team.[2]
On 2021, he signed with Círculo Gijón Baloncesto y Conocimiento to become an assistant coach.
|-| align="left" |Unión Financiera Baloncesto Oviedo| align="left" |2012-13|20||15||5||.7500 || align="center"||-| align="left" |Unión Financiera Baloncesto Oviedo| align="left" |2013-14|26||14||12||.5387 || align="center"||-| align="left" |Unión Financiera Baloncesto Oviedo| align="left" |2014-15|28||11||17||.3929 || align="center"||-| align="left" |Levitec Huesca| align="left" |2016-17|14||7||7||.5000 || align="center"||-| align="left" |Levitec Huesca| align="left" |2017-18|34||13||21||.3824 || align="center"||-| align="left" |Levitec Huesca| align="left" |2018-19|34||18||16||.5294 || align="center"||-| align="left" |Levitec Huesca| align="left" |2019-20|24||9||15||.3750 || align="center"||-|-class="sortbottom"| align="center" colspan=2|Career||206|||97|||109||.4709||