The 20-year-old midfielder is yet to make his senior debut for the Addicks, but he is now under contract at The Valley until the end of the 2016-17 season.
Gills boss Justin Edinburgh said of his new signing: "Oliver will give us another option in the centre of midfield and he has a good range of passing."
Muldoon's stint at Gillingham runs for the rest of the season.
Restore Data
| Team | P | W | D | L | F | A | GD | PTS | |
| C | Portsmouth | 46 | 28 | 13 | 5 | 78 | 41 | 37 | 97 |
| P | Derby CountyDerby | 46 | 28 | 8 | 10 | 78 | 37 | 41 | 92 |
| 3 | Bolton WanderersBolton | 46 | 25 | 12 | 9 | 86 | 51 | 35 | 87 |
| 4 | Peterborough UnitedPeterborough | 46 | 25 | 9 | 12 | 89 | 61 | 28 | 84 |
| 5 | Oxford UnitedOxford Utd | 46 | 22 | 11 | 13 | 79 | 56 | 23 | 77 |
| 6 | Barnsley | 46 | 21 | 13 | 12 | 82 | 64 | 18 | 76 |
| 7 | Lincoln CityLincoln | 46 | 20 | 14 | 12 | 65 | 40 | 25 | 74 |
| 8 | Blackpool | 46 | 21 | 10 | 15 | 65 | 48 | 17 | 73 |
| 9 | Stevenage | 46 | 19 | 14 | 13 | 57 | 46 | 11 | 71 |
| 10 | Wycombe WanderersWycombe | 46 | 17 | 14 | 15 | 60 | 55 | 5 | 65 |
| 11 | Leyton Orient | 46 | 18 | 11 | 17 | 53 | 55 | -2 | 65 |
| 12 | Wigan AthleticWigan | 46 | 20 | 10 | 16 | 63 | 56 | 7 | 62 |
| 13 | Exeter CityExeter | 46 | 17 | 10 | 19 | 46 | 61 | -15 | 61 |
| 14 | Northampton TownNorthampton | 46 | 17 | 9 | 20 | 57 | 66 | -9 | 60 |
| 15 | Bristol Rovers | 46 | 16 | 9 | 21 | 52 | 68 | -16 | 57 |
| 16 | Charlton AthleticCharlton | 46 | 11 | 20 | 15 | 64 | 65 | -1 | 53 |
| 17 | Reading | 46 | 16 | 11 | 19 | 68 | 70 | -2 | 53 |
| 18 | Cambridge UnitedCambridge | 46 | 12 | 12 | 22 | 39 | 61 | -22 | 48 |
| 19 | Shrewsbury TownShrewsbury | 46 | 13 | 9 | 24 | 35 | 67 | -32 | 48 |
| 20 | Burton Albion | 46 | 12 | 10 | 24 | 39 | 67 | -28 | 46 |
| R | Cheltenham TownCheltenham | 46 | 12 | 8 | 26 | 41 | 65 | -24 | 44 |
| R | Fleetwood TownFleetwood | 46 | 10 | 13 | 23 | 49 | 72 | -23 | 43 |
| R | Port Vale | 46 | 10 | 11 | 25 | 41 | 74 | -33 | 41 |
| R | Carlisle UnitedCarlisle | 46 | 7 | 9 | 30 | 41 | 81 | -40 | 30 |
| > League One Full Table | |||||||||
