Mathias Olesen

{{short description|Luxembourgish footballer (born 2001)}}

{{Use dmy dates|date=July 2024}}

{{Infobox football biography

| name = Mathias Olesen

| image =

| full_name = Mathias Flaga Olesen

| birth_date = {{Birth date and age|2001|March|21|df=y}}

| birth_place = Copenhagen, Denmark

| height = 1.88 m

| position = Midfielder

| currentclub = 1. FC Köln

| clubnumber = 47

| youthyears1 = 2017–2019

| youthclubs1 = Eintracht Trier

| youthyears2 = 2019–

| youthclubs2 = 1. FC Köln

| years1 = 2018–2019

| clubs1 = Eintracht Trier

| caps1 = 1

| goals1 = 0

| years2 = 2019–2023

| clubs2 = 1. FC Köln II

| caps2 = 55

| goals2 = 4

| years3 = 2022–

| clubs3 = 1. FC Köln

| caps3 = 41

| goals3 = 0

| years4 = 2024

| clubs4 = → Yverdon (loan)

| caps4 = 17

| goals4 = 0

| totalcaps =

| totalgoals =

| nationalyears1 = 2017

| nationalteam1 = Luxembourg U16

| nationalcaps1 = 6

| nationalgoals1 = 0

| nationalyears2 = 2017

| nationalteam2 = Luxembourg U17

| nationalcaps2 = 8

| nationalgoals2 = 1

| nationalyears3 = 2018

| nationalteam3 = Luxembourg U18

| nationalcaps3 = 2

| nationalgoals3 = 1

| nationalyears4 = 2018–2019

| nationalteam4 = Luxembourg U19

| nationalcaps4 = 8

| nationalgoals4 = 1

| nationalyears5 = 2018–2021

| nationalteam5 = Luxembourg U21

| nationalcaps5 = 11

| nationalgoals5 = 1

| nationalyears6 = 2021–

| nationalteam6 = Luxembourg

| nationalcaps6 = 30

| nationalgoals6 = 1

| medaltemplates =

| club-update = 23 May 2025

| nationalteam-update = 27 March 2025

}}

Mathias Flaga Olesen (born 21 March 2001) is a professional footballer who plays for {{German football updater|FCKöln}} club 1. FC Köln. Born in Denmark, he represents the Luxembourg national team.{{Soccerway|mathias-olesen/517933|accessdate=}}