| 09 Oct 18 | J. Bennett Jake Bennett |  Sheffield UnitedSHU | → |  ChesterfieldCHES | Loan |
| 01 Sept 18 | M. Cranie Martin Cranie | XXX | → | Sheffield UnitedSHU | Free |
| 31 Aug 18 | R. Leonard Ryan Leonard | Sheffield UnitedSHU | → |  MillwallMIL | Loan |
| 31 Aug 18 | C. Washington Conor Washington |  Queens Park RangersQPR | → | Sheffield UnitedSHU | Free |
| 31 Aug 18 | M. Johnson Marvin Johnson |  MiddlesbroughMID | → | Sheffield UnitedSHU | Loan |
| 31 Aug 18 | C. Lavery Caolan Lavery | Sheffield UnitedSHU | → |  BuryBURY | Loan |
| 13 Aug 18 | O. Norwood Oliver Norwood |  Brighton & Hove AlbionBHA | → | Sheffield UnitedSHU | Loan |
| 13 Aug 18 | O. Norwood Oliver Norwood | Brighton & Hove AlbionBHA | → | Sheffield UnitedSHU | Loan |
| 10 Aug 18 | L. Evans Lee Evans | Sheffield UnitedSHU | → |  Wigan AthleticWGA | Loan |
| 09 Aug 18 | R. Holmes Ricky Holmes | Sheffield UnitedSHU | → |  Oxford UnitedOXF | Loan |
| 02 Aug 18 | K. Bryan Kean Bryan |  Manchester CityMNC | → | Sheffield UnitedSHU | Free |
| 02 Aug 18 | Kean Bryan | Manchester CityMNC | → | Sheffield UnitedSHU | Undisclosed |
| 02 Aug 18 | K. Bryan Kean Bryan | Manchester CityMNC | → | Sheffield UnitedSHU | Free |
| 02 Aug 18 | Kean Bryan | Manchester CityMNC | → | Sheffield UnitedSHU | Undisclosed |
| 01 Aug 18 | B. Woodburn Ben Woodburn |  LiverpoolLIV | → | Sheffield UnitedSHU | Loan |
| 01 Aug 18 | B. Woodburn Ben Woodburn | LiverpoolLIV | → | Sheffield UnitedSHU | Loan |
| 24 Jul 18 | D. McGoldrick David McGoldrick |  Ipswich TownIPS | → | Sheffield UnitedSHU | Free |
| 20 Jul 18 | R. Slater Regan Slater | Sheffield UnitedSHU | → |  Carlisle UnitedCAR | Loan |
| 20 Jul 18 | C. Evans Ched Evans | Sheffield UnitedSHU | → |  Fleetwood TownFLE | Loan |
| 19 Jul 18 | J. Egan John Egan |  BrentfordBRE | → | Sheffield UnitedSHU | Undisclosed |
| 18 Jul 18 | G. Long George Long | Sheffield UnitedSHU | → |  Hull CityHUL | Undisclosed |
| 13 Jul 18 | H. Gilmour Harvey Gilmour | Sheffield UnitedSHU | → |  Tranmere RoversTRN | Loan |
| 06 Jul 18 | S. Graham Sam Graham | Sheffield UnitedSHU | → |  Oldham AthleticOLD | Loan |
| 03 Jul 18 | B. Heneghan Ben Heneghan | Sheffield UnitedSHU | → |  BlackpoolBLP | Loan |
| 03 Jul 18 | N. Thomas Nathan Thomas | Sheffield UnitedSHU | → |  Notts CountyNOTT | Loan |
| 01 Jul 18 | D. Brooks David Brooks | Sheffield UnitedSHU | → |  AFC BournemouthBOU | Undisclosed |
| 01 Jul 18 | D. Henderson Dean Henderson |  Manchester UnitedMAN | → | Sheffield UnitedSHU | Loan |
| 01 Jul 18 | S. Carruthers Samir Carruthers | Sheffield UnitedSHU | → | Oxford UnitedOXF | Loan |
| 01 Jul 18 | C. Donaldson Clayton Donaldson | Sheffield UnitedSHU | → |  Bolton WanderersBOL | Free |
| 01 Jul 18 | D. Brooks David Brooks | Sheffield UnitedSHU | → | AFC BournemouthBOU | Undisclosed |
| 01 Jul 18 | D. Henderson Dean Henderson | Manchester UnitedMAN | → | Sheffield UnitedSHU | Loan |
| 26 Jun 18 | J. Hanson James Hanson | Sheffield UnitedSHU | → |  Bradford CityBRD | Undisclosed |
| 19 Jun 18 | L. Reed Louis Reed | Sheffield UnitedSHU | → |  Peterborough UnitedPET | Undisclosed |
| 31 Jan 18 | N. Thomas Nathan Thomas | Sheffield UnitedSHU | → |  Shrewsbury TownSHR | Loan |
| 29 Jan 18 | C. Lavery Caolan Lavery | Sheffield UnitedSHU | → |  Rotherham UnitedROT | Loan |
| 15 Jan 18 | R. Holmes Ricky Holmes |  Charlton AthleticCHA | → | Sheffield UnitedSHU | Undisclosed |
| 11 Jan 18 | B. Whiteman Benjamin Whiteman | Sheffield UnitedSHU | → |  Doncaster RoversDON | Undisclosed |
| 10 Jan 18 | J. Wilson James Wilson | Manchester UnitedMAN | → | Sheffield UnitedSHU | Loan |
| 10 Jan 18 | L. Evans Lee Evans |  Wolverhampton WanderersWOL | → | Sheffield UnitedSHU | Undisclosed |
| 10 Jan 18 | J. Wilson James Wilson | Manchester UnitedMAN | → | Sheffield UnitedSHU | Loan |
| 09 Jan 18 | R. Leonard Ryan Leonard |  Southend UnitedSOUT | → | Sheffield UnitedSHU | Undisclosed |
| 03 Jan 18 | J. Hanson James Hanson | Sheffield UnitedSHU | → | BuryBURY | Loan |