The men's javelin throw event at the 1986 World Junior Championships in Athletics was held in Athens, Greece, at Olympic Stadium on 17 and 18 July.
| Gold | Vladimir Sasimovich | |
| Silver | Mark Roberson | |
| Bronze | Gavin Lovegrove |
18 July
| Rank | Name | Nationality | Result | Notes | |||
|---|---|---|---|---|---|---|---|
| align=left | align=left | 78.84 | |||||
| align=left | align=left | 74.24 | |||||
| align=left | align=left | | 74.22 | ||||
| 4 | align=left | align=left | 73.68 | ||||
| 5 | align=left | align=left |  | 70.96 | |||
| 6 | align=left | align=left |  | 70.96 | |||
| 7 | align=left | align=left | 69.96 | ||||
| 8 | align=left | align=left |  | 69.62 | |||
| 9 | align=left | align=left | 68.62 | ||||
| 10 | align=left | align=left |  | 67.34 | |||
| 11 | align=left | align=left |  | 65.24 | |||
| 12 | align=left | align=left |  | 64.94 |
17 Jul
| Rank | Name | Nationality | Result | Notes | |||
|---|---|---|---|---|---|---|---|
| 1 | align=left | align=left | 71.50 | Q | |||
| 2 | align=left | align=left | | 70.18 | Q | ||
| 3 | align=left | align=left | 67.64 | Q | |||
| 4 | align=left | align=left | 66.56 | Q | |||
| 5 | align=left | align=left | | 66.06 | |||
| 6 | align=left | align=left | 64.44 | ||||
| 7 | align=left | align=left |  | 62.96 | |||
| 8 | align=left | align=left | | 62.46 | |||
| 9 | align=left | align=left |  | 62.44 | |||
| 10 | align=left | align=left | 61.26 | ||||
| 11 | align=left | align=left | | 60.94 | |||
| 12 | align=left | align=left |  | 60.18 | |||
| 13 | align=left | align=left |  | 59.54 | |||
| 14 | align=left | align=left |  | 59.10 | |||
| 15 | align=left | align=left |  | 56.40 | |||
| 16 | align=left | align=left |  | 55.94 | |||
| 17 | align=left | align=left |  | 54.02 | |||
| 18 | align=left | align=left | 53.22 | ||||
| 19 | align=left | align=left | 51.56 |
| Rank | Name | Nationality | Result | Notes | |||
|---|---|---|---|---|---|---|---|
| 1 | align=left | align=left | 72.16 | Q | |||
| 2 | align=left | align=left | 69.62 | Q | |||
| 3 | align=left | align=left | | 69.20 | Q | ||
| 4 | align=left | align=left | | 68.60 | Q | ||
| 5 | align=left | align=left | | 67.76 | Q | ||
| 6 | align=left | align=left | | 67.60 | Q | ||
| 7 | align=left | align=left | | 66.90 | q | ||
| 8 | align=left | align=left | | 66.24 | q | ||
| 9 | align=left | align=left |  | 66.22 | |||
| 10 | align=left | align=left | 66.08 | ||||
| 11 | align=left | align=left |  | 65.74 | |||
| 12 | align=left | align=left | 65.54 | ||||
| 13 | align=left | align=left |  | 65.24 | |||
| 14 | align=left | align=left | | 65.02 | |||
| 15 | align=left | align=left | 65.00 | ||||
| 16 | align=left | align=left | | 61.98 | |||
| 17 | align=left | align=left | 60.98 | ||||
| 18 | align=left | align=left | | 60.40 | |||
| 19 | align=left | align=left | 56.06 | ||||
| 20 | align=left | align=left | 50.10 | ||||
| 21 | align=left | align=left | 49.18 | ||||
| 22 | align=left | align=left |  | 42.26 |
According to an unofficial count, 41 athletes from 30 countries participated in the event.