Gunnar Nielsen (Argentine footballer) should not be confused with Gunnar Nielsen (Faroese footballer).
| Gunnar Nielsen | |
| Fullname: | Gunnar Guillermo Nielsen |
| Birth Date: | 12 October 1983 |
| Birth Place: | Posadas, Misiones, Argentina |
| Currentclub: | Hillerød Fodbold |
| Clubnumber: | TBA |
| Position: | Midfielder |
| Youthclubs1: | Guaraní Antonio Franco |
| Years1: | 2000 |
| Years2: | 2000–2001 |
| Years3: | 2002 |
| Years4: | 2002–2005 |
| Years5: | 2005–2006 |
| Years6: | 2006–2007 |
| Years7: | 2007–2008 |
| Years8: | 2008–2009 |
| Years9: | 2010–2011 |
| Years10: | 2011–2012 |
| Years11: | 2012 |
| Years12: | 2012–2014 |
| Years13: | 2014– |
| Clubs9: | Kolding FC |
| Clubs10: | Kristianstads FF |
| Clubs11: | Östers IF |
| Clubs12: | IF Skjold Birkerød |
| Clubs13: | Hillerød Fodbold |
| Caps7: | 25 |
| Caps8: | 20 |
| Caps9: | 22 |
| Caps10: | 10 |
| Goals7: | 6 |
| Goals8: | 7 |
| Goals9: | 5 |
| Goals10: | 8 |
Gunnar Guillermo Nielsen (pronounced as /es/; born 12 October 1983 in Posadas, Misiones) is an Argentine football player of Danish descent, currently playing for Hillerød GI. He previously represented FC Fredericia and Kolding FC.[1]