| John Castillo | |
| Fullname: | John Eider Castillo Diago |
| Birth Date: | 21 September 1983 |
| Birth Place: | Colombia |
| Position: | Forward |
| Years1: | 2001–2002 |
| Years2: | 2003 |
| Clubs2: | FBC Melgar |
| Years3: | 2004–2007 |
| Years4: | 2007–2009 |
| Clubs4: | Dragón |
| Years5: | 2009–2011 |
| Years6: | 2011 |
| Clubs6: | Alianza |
| Caps6: | 7 |
| Goals6: | 0 |
| Years7: | 2012 |
| Caps7: | 14 |
| Goals7: | 2 |
| Years8: | 2012–2013 |
| Clubs8: | Sacachispas |
| Years9: | 2013 |
| Clubs9: | Deportivo Iztapa |
| Caps9: | 8 |
| Goals9: | 2 |
| Years10: | 2014 |
| Clubs10: | Platense |
| Pcupdate: | 13 August 2011 |
John Eider Castillo Diago (born September 21, 1983) is a Colombian footballer who currently plays for UES in El Salvador.