Middlesbrough FC Players
| Name | Position | Country |
| A Johnson | Midfielder | England |
| A Ormston | Midfielder | England |
| A Price | Forward | England |
| A Thompson | Forward | England |
| A Warburton | Midfielder | England |
| Aaron Connolly | Forward | Ireland |
| Aaron Ramsey | Midfielder | England |
| Abdoulaye Kante | Midfielder | Ivory Coast |
| Abel Xavier | Defender | Portugal |
| Abraham Jones | Defender | England |
| Adam Clayton | Midfielder | England |
| Adam Forshaw | Midfielder | England |
| Adam Hammill | Forward | England |
| Adam Jackson | Defender | England |
| Adam Johnson | Forward | England |
| Adam Reach | Midfielder | England |
| Adama Traroe | Forward | Spain |
| Aden Flint | Defender | England |
| Adilson Malanda | Defender | France |
| Adlene Guedioura | Midfielder | Algeria |
| Afonso Alves | Forward | Brazil |
| Aidan Morris | Midfielder | United States |
| Ajay Matthews | Forward | England |
| Alan Browne | Midfielder | Ireland |
| Alan Comfort | Forward | England |
| Alan Foggon | Forward | England |
| Alan McNeill | Midfielder | England |
| Alan McRobbie | Defender | England |
| Alan Miller | Goalkeeper | England |
| Alan Moody | Defender | England |
| Alan Moore | Forward | Ireland |
| Alan Murray | Midfielder | England |
| Alan Peacock | Forward | England |
| Alan Ramage | Defender | England |
| Alan Roberts | Midfielder | England |
| Alan Rodgerson | Forward | England |
| Alan Walsh | Forward | Scotland |
| Alan Willey | Forward | England |
| Alan Wright | Midfielder | England |
| Albert Adomah | Forward | England |
| Albert Davies | Midfielder | England |
| Albert Elkes | Forward | England |
| Albert Hasell | Goalkeeper | England |
| Albert Ross | Defender | England |
| Albert Simpson | Forward | England |
| Alen Boksic | Forward | Croatia |
| Alex Bangura | Defender | Sierra Leone |
| Alex Baptiste | Midfielder | England |
| Alex Gilbert | Forward | Ireland |
| Alex Linwood | Forward | Scotland |
| Alex McCrae | Forward | England |
| Alex McCulloch | Forward | Scotland |
| Alex Mowett | Midfielder | England |
| Alex Nimely-Tchuimeni | Forward | Liberia |
| Alex Pattison | Midfielder | England |
| Alex Smith | Defender | England |
| Alexander Campbell | Defender | Scotland |
| Alexander Cochrane | Forward | Scotland |
| Alexander Fraser | Midfielder | Scotland |
| Alexander Robinson | Forward | England |
| Alexander Wardrope | Defender | England |
| Alf Maitland | Defender | Scotland |
| Alf Wood | Midfielder | England |
| Alfie Jones | Defender | England |
| Alfred Common | Forward | England |
| Alfred Priest | Forward | England |
| Allan Johnston | Midfielder | Scotland |
| Allan Kernaghan | Defender | Ireland |
| Alonzo Poulton | Midfielder | England |
| Alun Armstrong | Forward | England |
| Alvaro Negredo | Forward | Spain |
| Amario Cozier-Duberry | Forward | England |
| Andraz Sporar | Forward | Slovenia |
| Andre Bikey | Midfielder | Cameroon |
| Andrew Carr | Defender | England |
| Andrew Davidson | Defender | England |
| Andrew Davies | Defender | England |
| Andrew Jackson | Defender | England |
| Andrew McCowie | Forward | Scotland |
| Andrew Nesbit Wilson | Forward | Scotland |
| Andrew Ramsey | Defender | England |
| Andrew Taylor | Defender | England |
| Andy Aitken | Defender | Scotland |
| Andy Campbell | Forward | England |
| Andy Collett | Goalkeeper | England |
| Andy Crawford | Midfielder | England |
| Andy Dibble | Goalkeeper | England |
| Andy Donaldson | Forward | England |
| Andy Halliday | Forward | Scotland |
| Andy Lonergan | Goalkeeper | England |
| Andy McCreesh | Defender | Scotland |
| Andy McGuigan | Midfielder | Scotland |
| Andy Payton | Forward | Scotland |
| Andy Peake | Midfielder | England |
| Andy Strong | Defender | England |
| Andy Todd | Defender | England |
| Andy Townsend | Midfielder | Ireland |
| Anfernee Dijksteel | Defender | The Netherlands |
| Anthony Ormerod | Forward | England |
| Antonio Barragan | Defender | Spain |
| Archibald Wilson | Forward | England |
| Archie Baptiste | Defender | England |
| Archie Stephens | Forward | Scotland |
| Arnold Watson | Midfielder | England |
| Arthhur Brown | Forward | England |
| Arthur Cunliffe | Midfielder | England |
| Arthur Davies | Midfielder | Wales |
| Arthur Fitzsimons | Forward | Ireland |
| Arthur Horsfield | Forward | England |
| Arthur Kaye | Forward | England |
| Arthur Layton | Defender | England |
| Arthur Lightening | Goalkeeper | South Africa |
| Arthur Rigby | Midfielder | England |
| Arthur Stevenson | Midfielder | England |
| Arthur Urquhart | Midfielder | England |
| Ashley Fletcher | Forward | England |
| Ashley Phillips | Defender | England |
| Aynsley Pears | Goalkeeper | England |