| 28. Round | 06/02/2021 | Newport County | - | Grimsby Town | 1:0 | ||||
| 31. Round | 23/02/2021 | Grimsby Town | - | Crawley Town | 2:1 |  |
 |
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| 32. Round | 27/02/2021 | Harrogate Town | - | Grimsby Town | 1:0 | ||||
| 33. Round | 02/03/2021 | Grimsby Town | - | Leyton Orient | 0:1 | ||||
| 36. Round | 13/03/2021 | Grimsby Town | - | Colchester United | 0:0 | ||||
| 37. Round | 20/03/2021 | Mansfield Town | - | Grimsby Town | 2:2 |
Wales