| 7. Round | 20/10/2020 | Grimsby Town | - | Harrogate Town | 1:2 | ||||
| 19. Round | 19/12/2020 | Grimsby Town | - | Scunthorpe United | 1:0 |  |
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| 4. Round | 22/12/2020 | Grimsby Town | - | Bradford City | 1:2 | ||||
| 24. Round | 16/01/2021 | Grimsby Town | - | Southend United | 0:0 | |
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| 25. Round | 23/01/2021 | Scunthorpe United | - | Grimsby Town | 3:0 | ||||
| 27. Round | 30/01/2021 | Grimsby Town | - | Stevenage FC | 1:2 | ||||
| 37. Round | 20/03/2021 | Mansfield Town | - | Grimsby Town | 2:2 | ||||
| 26. Round | 23/03/2021 | Barrow AFC | - | Grimsby Town | 0:1 |  |
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| 38. Round | 27/03/2021 | Grimsby Town | - | Walsall FC | 1:1 | ||||
| 39. Round | 02/04/2021 | Salford City | - | Grimsby Town | 1:1 | ||||
| 41. Round | 10/04/2021 | Bradford City | - | Grimsby Town | 1:0 | ||||
| 42. Round | 17/04/2021 | Grimsby Town | - | Bolton Wanderers | 2:1 | ||||
| 43. Round | 20/04/2021 | Grimsby Town | - | Morecambe FC | 0:3 | ||||
| 44. Round | 24/04/2021 | Oldham Athletic | - | Grimsby Town | 1:2 | ||||
| 30. Round | 27/04/2021 | Exeter City | - | Grimsby Town | 3:2 | ||||
| 45. Round | 01/05/2021 | Grimsby Town | - | Port Vale FC | 1:0 | ||||
| 46. Round | 08/05/2021 | Cambridge United | - | Grimsby Town | 3:0 |
England