A timeline of major things that happened in the series, by year, month and day. This includes character births. Question marks (?) are included when the date is uncertain or only calculated based on clues. Some birth dates may be inconsistent with others.
| Date | Event | Citation |
|---|---|---|
| 1946 | Hiroshi Uchiyamada is born. | |
| 1964 | Misuzu Daimon is born. | She is 34 in the manga. |
| July 27, 1966 | Mariko Izumo is born. | SJG Chapter 6 |
| September 11, 1966 | Ayumi Murakoshi is born. | SJG Chapter 7 |
| 1969 | Hiroshi Uchiyamada starts working as a teacher. | GTO Chapter 86; Uchiyamada mentions he's been teaching for 29 years. |
| 1970 (?) | Julia Murai is born. | |
| June 8, 1974 | Nao Kadena is born. | This is probably only accurate for the anime, since in the manga she is around the same age as Mariko. |
| August 3, 1975 | Eikichi Onizuka is born. | SJG Chapter 1 |
| February 18, 1976 | Suguru Teshigawara is born. | |
| March 30, 1976 | Ryuji Danma is born. | SJG Chapter 1 |
| April 2, 1977 | Toshiyuki Saejima is born. | |
| March 19, 1978 | Azusa Fuyutsuki is born. | |
| 1983-84 (?) | Kunio Murai is born. | |
| November 9, 1984 | Urumi Kanzaki is born. | |
| June 12, 1985 | Kouji Fujiyoshi is born. | |
| September 25, 1985 | Tomoko Nomura is born. | |
| September 28, 1984 | Mayu Wakui is born. | |
| October 24, 1985 | Tadaaki Kusano is born. | |
| November 1, 1985 | Miyabi Aizawa is born. | |
| Ayumi's boyfriend dies in a motorcycle accident. | ||
| late 1989-early 1990 (?) | Events of Bad Company -- Eikichi and Ryuji meet and get their motorcycles. | |
| 1989 (?) | First Shonan War involving the Midnight Angels. | SJG Chapter 122 mentions the first Midnight Angel was broken up 3 years ago |
| Kyosuke Masaki dies in a motorcycle accident. | ||
| August-September 1991 | Eikichi Onizuka and Ryuji Danma transfer to Tsujido High School. | |
| The Oni-Baku fight the Kamakura Wild Dogs (Saejima and Kamata), and afterwards become friends. | ||
| Fumiya Shindoji declares war on the Oni-Baku. | ||
| Ryuji and Ayumi get engaged, but she leaves him. | ||
| April 7, 1992 | The Oni-Baku duo and several of their friends are held back a year in high school, with Yoko Minamino as their new teacher. | SJG Chapter 75 |
| Ryuji meets Nagisa Nagase. | ||
| Summer 1992 | Junya Akutsu is released from juvenile detention and reforms the Midnight Angels, starting the Second Shonan War. | |
| Natsuki Smith-Mizuki, thought to be dead, returns to Kanagawa and fights the Yokohama Cavalry. In the aftermath, Jun Kamata leaves for the USA. | ||
| Spring 1993 | Nao Kadena begins working as a teacher at Tsujido. | |
| April 1993 | Eikichi and Ryuji fake their deaths and move to Tokyo. | SJG Chapter 267 |
| 1995 (?) | Urumi and Ms. Fujimori have a falling-out. | |
| 1997 (?) | Miyabi tries to seduce Mr. Ōgi, but he rejects her advances. In revenge, she spreads a rumor accusing him of sexually assaulting her, which results in Takumi Ishida attacking him, Ogi resigning, and Takumi being expelled. This begins Class 4's anti-teacher campaign. | |
| Onizuka gets a teaching degree. | ||
| April 23, 1997 | Onizuka starts working as a teacher at Holy Forest Academy. | GTO Chapter 15; this may be a mistranslation |
| 1998-1999 (?) | Based on the ages of the students and their birthdates, 1999 is the most likely date. However, Onizuka would be 23, not 22. | |
| Onizuka enters Tomoko Nomura in a beauty contest. | ||
| May 1998 | Urumi Kanzaki starts coming back to school, joining class 3-4. | In GTO Chapter 64, Urumi mentions she has "10 more months until school ends". Japanese school years end in March. |
| June-July 1998 | Class 3-4 takes a trip to Okinawa. | In GTO Chapter 92, before they go on the trip, Onizuka says he's been teaching for three months, so that would be around late June-early July. |
| July 1998 | Urumi and Miyabi both try to kill themselves. Teshigawara kidnaps Azusa. | GTO Chapter 142 says it's the end of the semester, which in Japan is around mid-July. |
| Summer 1998 | Events of GTO: Shonan 14 Days -- Onizuka flees to his hometown of Shonan for two weeks. | |
| Misuzu Daimon is appointed headmistress of Holy Forest Academy. | ||
| Onizuka goes into a coma, and reawakens in time to save Misuzu Daimon from the burning school. | ||
| late 1999-early 2000 | Onizuka goes to prison. |