The men's 800 metres event at the 2016 IAAF World U20 Championships was held at Zdzisław Krzyszkowiak Stadium on 22, 23 and 24 July.
| Gold | Kipyegon Bett | |
| Silver | ||
| Bronze | Mostafa Smaili |
| Standing records prior to the 2016 IAAF World U20 Championships in Athletics | |||||
|---|---|---|---|---|---|
| World Junior Record | 1:41.73 | London, United Kingdom | 9 August 2012 | ||
| Championship Record | 1:43.79 | Barcelona, Spain | 15 July 2012 | ||
| World Junior Leading | 1:43.55 | Eugene, United States | 10 June 2016 | ||
Qualification: First 4 of each heat (Q) and the 4 fastest times (q) qualified for the semifinals.[1]
| Rank | Heat | Name | Nationality | Time | Note | |
|---|---|---|---|---|---|---|
| 1 | 3 | 1:48.40 | Q | |||
| 2 | 3 | 1:48.45 | Q | |||
| 3 | 3 | 1:48.69 | Q | |||
| 4 | 3 | 1:48.82 | Q | |||
| 5 | 2 | 1:48.95 | Q | |||
| 6 | 3 | 1:49.05 | q | |||
| 7 | 2 | 1:49.20 | Q | |||
| 8 | 2 | 1:49.29 | Q | |||
| 9 | 3 | 1:49.32 | q | |||
| 10 | 5 | 1:49.69 | Q | |||
| 11 | 2 | 1:49.69 | Q | |||
| 12 | 1 | 1:49.82 | Q | |||
| 13 | 5 | 1:49.97 | Q | |||
| 14 | 2 | 1:50.18 | q | |||
| 15 | 1 | 1:50.19 | Q | |||
| 16 | 5 | 1:50.33 | Q | |||
| 17 | 1 | 1:50.40 | Q | |||
| 18 | 5 | 1:50.69 | Q | |||
| 19 | 5 | 1:50.77 | q | |||
| 19 | 4 | 1:50.82 | Q | |||
| 20 | 1 | 1:50.88 | Q | |||
| 21 | 2 | 1:50.93 | ||||
| 23 | 4 | 1:50.97 | Q | |||
| 24 | 5 | 1:51.39 | ||||
| 25 | 1 | 1:51.73 | ||||
| 26 | 4 | 1:51.77 | Q | |||
| 27 | 4 | 1:52.03 | Q | |||
| 28 | 1 | 1:52.42 | ||||
| 29 | 4 | 1:52.54 | ||||
| 30 | 4 | 1:53.61 | ||||
| 31 | 1 | 1:54.26 | PB | |||
| 32 | 2 | 1:55.92 | ||||
| 33 | 4 | 1:57.74 |
Qualification: First 2 of each heat (Q) and the 2 fastest times (q) qualified for the final.[2]
| Rank | Heat | Name | Nationality | Time | Note | |
|---|---|---|---|---|---|---|
| 1 | 3 | 1:46.37 | Q | |||
| 2 | 1 | 1:46.51 | Q | |||
| 3 | 1 | 1:47.11 | Q, NU20R | |||
| 4 | 1 | 1:47.13 | q | |||
| 5 | 3 | 1:47.25 | Q | |||
| 6 | 1 | 1:47.49 | q | |||
| 7 | 3 | 1:47.53 | ||||
| 8 | 3 | 1:47.53 | PB | |||
| 9 | 1 | 1:47.65 | PB | |||
| 10 | 1 | 1:47.70 | PB | |||
| 11 | 1 | 1:48.06 | NU20R | |||
| 12 | 2 | 1:48.27 | Q | |||
| 13 | 2 | 1:48.31 | Q, PB | |||
| 14 | 2 | 1:48.49 | ||||
| 15 | 2 | 1:48.63 | ||||
| 16 | 2 | 1:48.88 | ||||
| 17 | 3 | 1:48.91 | ||||
| 18 | 2 | 1:49.43 | ||||
| 19 | 3 | 1:49.44 | ||||
| 20 | 3 | 1:49.58 | ||||
| 21 | 2 | 1:49.84 | ||||
| 22 | 1 | 1:51.27 | ||||
| 23 | 2 | 1:51.76 | ||||
| 24 | 3 | 1:53.86 |
| Rank | Name | Nationality | Time | Note | |
|---|---|---|---|---|---|
| 1:44.95 | SB | ||||
| 1:45.50 | |||||
| 1:46.02 | |||||
| 4 | 1:46.70 | ||||
| 5 | 1:47.33 | ||||
| 6 | 1:47.38 | ||||
| 7 | 1:47.68 | ||||
| 8 | 1:48.40 |