The 25-year-old, who spent the end of last season on loan with the Shrimpers, has penned a two-year contract at Roots Hall.
"I'm really pleased to have brought Stephen back and not many teams at this level will have options like we do out wide now," manager Phil Brown told the Southend Echo.
McLaughlin made 12 appearances for Forest after joining the club from Derry City in 2013.
Restore Data
| Team | P | W | D | L | F | A | GD | PTS | |
| C | Manchester CityMan City | 38 | 28 | 7 | 3 | 96 | 34 | 62 | 91 |
| 2 | Arsenal | 38 | 28 | 5 | 5 | 91 | 29 | 62 | 89 |
| 3 | Liverpool | 38 | 24 | 10 | 4 | 86 | 41 | 45 | 82 |
| 4 | Aston Villa | 38 | 20 | 8 | 10 | 76 | 61 | 15 | 68 |
| 5 | Tottenham HotspurSpurs | 38 | 20 | 6 | 12 | 74 | 61 | 13 | 66 |
| 6 | Chelsea | 38 | 18 | 9 | 11 | 77 | 63 | 14 | 63 |
| 7 | Newcastle UnitedNewcastle | 38 | 18 | 6 | 14 | 85 | 62 | 23 | 60 |
| 8 | Manchester UnitedMan Utd | 38 | 18 | 6 | 14 | 57 | 58 | -1 | 60 |
| 9 | West Ham UnitedWest Ham | 38 | 14 | 10 | 14 | 60 | 74 | -14 | 52 |
| 10 | Crystal Palace | 38 | 13 | 10 | 15 | 57 | 58 | -1 | 49 |
| 11 | Brighton & Hove AlbionBrighton | 38 | 12 | 12 | 14 | 55 | 62 | -7 | 48 |
| 12 | Bournemouth | 38 | 13 | 9 | 16 | 54 | 67 | -13 | 48 |
| 13 | Fulham | 38 | 13 | 8 | 17 | 55 | 61 | -6 | 47 |
| 14 | Wolverhampton WanderersWolves | 38 | 13 | 7 | 18 | 50 | 65 | -15 | 46 |
| 15 | Everton | 38 | 13 | 9 | 16 | 40 | 51 | -11 | 40 |
| 16 | Brentford | 38 | 10 | 9 | 19 | 56 | 65 | -9 | 39 |
| 17 | Nottingham ForestNott'm Forest | 38 | 9 | 9 | 20 | 49 | 67 | -18 | 32 |
| R | Luton TownLuton | 38 | 6 | 8 | 24 | 52 | 85 | -33 | 26 |
| R | Burnley | 38 | 5 | 9 | 24 | 41 | 78 | -37 | 24 |
| R | Sheffield UnitedSheff Utd | 38 | 3 | 7 | 28 | 35 | 104 | -69 | 16 |
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