| Mateusz Ostaszewski | |
| Birth Date: | 1998 3, df=yes |
| Birth Place: | Białystok, Poland |
| Position: | Attacking midfielder |
| Youthyears1: | –2013 |
| Youthclubs1: | Jagiellonia Białystok |
| Youthyears2: | 2013–2015 |
| Youthclubs2: | Borussia Dortmund |
| Years1: | 2015–2019 |
| Caps1: | 0 |
| Goals1: | 0 |
| Clubs1: | Jagiellonia Białystok |
| Years2: | 2016 |
| Caps2: | 14 |
| Goals2: | 0 |
| Clubs2: | → Rozwój Katowice (loan) |
| Years3: | 2017–2018 |
| Caps3: | 4 |
| Goals3: | 2 |
| Clubs3: | → Widzew Łódź (loan) |
| Years4: | 2018–2019 |
| Caps4: | 39 |
| Goals4: | 4 |
| Clubs4: | → Olimpia Zambrów (loan) |
| Years5: | 2019–2020 |
| Caps5: | 17 |
| Goals5: | 1 |
| Clubs5: | Olimpia Zambrów |
| Nationalyears1: | 2013 |
| Nationalcaps1: | 2 |
| Nationalgoals1: | 0 |
| Nationalyears2: | 2014–2015 |
| Nationalcaps2: | 10 |
| Nationalgoals2: | 1 |
| Nationalyears3: | 2015 |
| Nationalcaps3: | 3 |
| Nationalgoals3: | 1 |
Mateusz Ostaszewski (born 27 March 1998) is a Polish former professional footballer who played as an attacking midfielder.
Due to recurring injury issues, he retired in August 2020.[1]