| Petter Mathias Olsen | |
| Birth Date: | 13 January 1998 |
| Currentclub: | Grorud |
| Clubnumber: | 17 |
| Position: | midfielder |
| Youthclubs1: | Fjellhamar |
| Youthclubs2: | Lillestrøm |
| Years1: | 2015–2019 |
| Clubs1: | Lillestrøm |
| Caps1: | 2 |
| Goals1: | 0 |
| Years2: | 2017 |
| Clubs2: | → Strømmen (loan) |
| Caps2: | 9 |
| Goals2: | 0 |
| Years3: | 2018 |
| Clubs3: | → Strømmen (loan) |
| Caps3: | 17 |
| Goals3: | 2 |
| Years4: | 2019 |
| Clubs4: | → Hamarkameratene (loan) |
| Caps4: | 9 |
| Goals4: | 0 |
| Years5: | 2019 |
| Clubs5: | → Grorud (loan) |
| Caps5: | 1 |
| Goals5: | 0 |
| Years6: | 2020– |
| Caps6: | 0 |
| Goals6: | 0 |
| Nationalyears1: | 2017 |
| Nationalteam1: | Norway U19 |
| Nationalcaps1: | 4 |
| Nationalgoals1: | 0 |
| Pcupdate: | 31 May 2020 |
| Ntupdate: | 31 May 2020 |
Petter Mathias Olsen (born 13 January 1998) is a Norwegian football midfielder who currently plays for Grorud on loan from Lillestrøm.