| Marnus van der Merwe | |
| Fullname: | Marthinus Stephanus van der Merwe |
| Birth Date: | 17 February 1997 |
| Birth Place: | Nelspruit, South Africa |
| School: | Hoërskool Nelspruit, Nelspruit |
| Position: | Hooker |
| Currentclub: | / |
| Youthyears1: | 2010–2015 |
| Youthyears2: | 2016–2018 |
| Years1: | 2017–2019 |
| Apps1: | 13 |
| Points1: | 25 |
| Years2: | 2017–present |
| Apps2: | 26 |
| Points2: | 55 |
| Years3: | 2018–present |
| Apps3: | 12 |
| Points3: | 0 |
| Clubupdate: | 8 September 2021 |
Marthinus Stephanus van der Merwe (born 17 February 1997) is a South African rugby union player for the in the Pro14, the in the Currie Cup and the in the Rugby Challenge. His regular position is hooker.