| 1 | Sat 5 Sep 2020 | 11-1 v MorecambeGrimsby Town 1-1 Morecambe | Carabao Cup First Round North |
| 2 | Sat 19 Sep 2020 | 10-4 v Salford CityGrimsby Town 0-4 Salford City | Sky Bet League Two |
| 3 | Sat 10 Oct 2020 | 10-0 v Bolton WanderersBolton Wanderers 0-0 Grimsby Town | Sky Bet League Two |
| 4 | Tue 13 Oct 2020 | 13-1 v Cheltenham TownCheltenham Town 1-3 Grimsby Town | Sky Bet League Two |
| 5 | Sat 17 Oct 2020 | 13-2 v Leyton OrientLeyton Orient 2-3 Grimsby Town | Sky Bet League Two |
| 6 | Tue 20 Oct 2020 | 11-2 v Harrogate TownGrimsby Town 1-2 Harrogate Town | Sky Bet League Two |
| 7 | Sat 24 Oct 2020 | 11-1 v Carlisle UnitedGrimsby Town 1-1 Carlisle United | Sky Bet League Two |
| 8 | Tue 27 Oct 2020 | 10-1 v Forest Green RoversForest Green Rovers 1-0 Grimsby Town | Sky Bet League Two |
| 9 | Sat 31 Oct 2020 | 10-0 v StevenageStevenage 0-0 Grimsby Town | Sky Bet League Two |
| 10 | Tue 3 Nov 2020 | 1 1-0 v BarrowGrimsby Town 1-0 Barrow | Sky Bet League Two |
| 11 | Tue 17 Nov 2020 | 10-3 v Hull CityHull City 3-0 Grimsby Town | Papa John’s Trophy Group 10 |
| 12 | Sat 21 Nov 2020 | 10-5 v Tranmere RoversTranmere Rovers 5-0 Grimsby Town | Sky Bet League Two |
| 13 | Tue 24 Nov 2020 | 12-1 v Crawley TownCrawley Town 1-2 Grimsby Town | Sky Bet League Two |
| 14 | Tue 1 Dec 2020 | 11-4 v Exeter CityGrimsby Town 1-4 Exeter City | Sky Bet League Two |
| 15 | Sat 5 Dec 2020 | 11-2 v Colchester UnitedColchester United 2-1 Grimsby Town | Sky Bet League Two |
| 16 | Sat 19 Dec 2020 | 11-0 v Scunthorpe UnitedGrimsby Town 1-0 Scunthorpe United | Sky Bet League Two |
| 17 | Tue 22 Dec 2020 | 11-2 v Bradford CityGrimsby Town 1-2 Bradford City | Sky Bet League Two |
| 18 | Sat 26 Dec 2020 | 11-3 v MorecambeMorecambe 3-1 Grimsby Town | Sky Bet League Two |
| 19 | Sat 9 Jan 2021 | 10-3 v Port ValePort Vale 3-0 Grimsby Town | Sky Bet League Two |
| 20 | Sat 16 Jan 2021 | 10-0 v Southend UnitedGrimsby Town 0-0 Southend United | Sky Bet League Two |
| 21 | Sat 23 Jan 2021 | 10-3 v Scunthorpe UnitedScunthorpe United 3-0 Grimsby Town | Sky Bet League Two |
| 22 | Sat 30 Jan 2021 | 1 1-2 v StevenageGrimsby Town 1-2 Stevenage | Sky Bet League Two |
| 23 | Sat 13 Mar 2021 | 10-0 v Colchester UnitedGrimsby Town 0-0 Colchester United | Sky Bet League Two |
| 24 | Wed 17 Mar 2021 | 10-0 v Tranmere RoversGrimsby Town 0-0 Tranmere Rovers | Sky Bet League Two |
| 25 | Sat 20 Mar 2021 | 12-2 v Mansfield TownMansfield Town 2-2 Grimsby Town | Sky Bet League Two |
| 26 | Tue 23 Mar 2021 | 11-0 v BarrowBarrow 0-1 Grimsby Town | Sky Bet League Two |
| 27 | Sat 27 Mar 2021 | 11-1 v WalsallGrimsby Town 1-1 Walsall | Sky Bet League Two |
| 28 | Fri 2 Apr 2021 | 11-1 v Salford CitySalford City 1-1 Grimsby Town | Sky Bet League Two |
| 29 | Mon 5 Apr 2021 | 11-1 v Cheltenham TownGrimsby Town 1-1 Cheltenham Town | Sky Bet League Two |
| 30 | Sat 10 Apr 2021 | 10-1 v Bradford CityBradford City 1-0 Grimsby Town | Sky Bet League Two |
| 31 | Sat 17 Apr 2021 | 12-1 v Bolton WanderersGrimsby Town 2-1 Bolton Wanderers | Sky Bet League Two |
| 32 | Tue 20 Apr 2021 | 10-3 v MorecambeGrimsby Town 0-3 Morecambe | Sky Bet League Two |
| 33 | Sat 24 Apr 2021 | 12-1 v Oldham AthleticOldham Athletic 1-2 Grimsby Town | Sky Bet League Two |
| 34 | Tue 27 Apr 2021 | 12-3 v Exeter CityExeter City 3-2 Grimsby Town | Sky Bet League Two |
| 35 | Sat 1 May 2021 | 11-0 v Port ValeGrimsby Town 1-0 Port Vale | Sky Bet League Two |
| 36 | Sat 8 May 2021 | 10-3 v Cambridge UnitedCambridge United 3-0 Grimsby Town | Sky Bet League Two |