| 1905 | The Boer War and Paul David Memorial Concert Hall and Gymnasium (now The Theatre) opens |
| 1908-1915 | The Revd Harry Ward McKenzie, Headmaster |
| 1910 | The Old Music School completed |
| 1914 | The Middle Playing Fields purchased |
| 1915 | The Chapel Organ installed (extensively refurbished in 1965) |
| 1916-1934 | The most Revd Reginald Herbert Owen, Headmaster |
| 1919 | The (original) Lodge (The Lower School) moves to Nevill Holt, and is no longer an integral part of Uppingham School |
| 1921 | The First World War Memorial Shrine in the Chapel is dedicated |
| 1923-1929 | East Block classrooms and Memorial Hall built |
| 1923 | Second Cricket Pavilion on The Upper built |
| 1926 | Scheme for the School to purchase the boarding houses from individual Housemasters is established |
| 1928 | Constables opens |
| 1928-1929 | Masons’ Lawn laid and Masons’ Gate erected |
| 1929 | The Leicester Pavilion completed |
| 1931 | The Memorial Hall organ installed |
| 1934-1944 | John Frederick Wolfenden (Lord Wolfenden), Headmaster |
| 1935 | The Sanatorium opens (combining Woodfield Sanatorium and Fairfield Isolation block) |
| 1939-1946 | Kingswood School shares the facilities at Uppingham throughout WWII |
| 1940 | Redgate closed |
| 1944-1965 | Martin Lloyd, Headmaster |
| 1950 | WWII Memorial and new Library opens |
| 1957 | The New Science Block completed |
| 1964 | School Shop opens for business |
| 1965 | Chapel Extension built to accommodate growing numbers at the School The Thring Centre opens and houses the Design andTechnology Department |
| 1965-1974 | John Caress Royds, Headmaster |
| 1969 | Memorial Hall divided horizontally to accommodate two floors Community Service starts (known as the Pioneer Group or Public Service for the first few years) |
| 1970 | Sports Centre built |
| 1972 | Theatre opens The Headmaster ceases to be Housemaster of School House |
| 1975-1982 | Coll MacDonald, Headmaster |
| 1975 | Fairfield opens as Uppingham’s first Sixth Form girls’ house |
| 1981 | New Music School and Buttery open |
| 1982-1991 | Nicholas Raymond Bomford, Headmaster |
| 1984 | Quatercentenary celebrations; The Queen visits |
| 1986 | Johnson's, Uppingham’s second Sixth Form girls’ house, opens |
| 1989 | Maths Block constructed |
| 1991 | Lee Astro laid to provide an all weather sport surface |
| 1991-2006 | Stephen Charles Winkley, Headmaster |
| 1993 | The Lodge opens as a Sixth Form boys' house |
| 1994 | The Lodge becomes a Sixth Form girls' house Woodfield opens as a new Lower School for entry at 11+ |
| 1995 | The Leonardo Centre opens to house Art, Design and Technology |
| 1997 | Thring Centre becomes the Sixth Form Centre |
| 1998 | Arboretum (between Spring Back Way and The Middle Playing Fields) established |