The 2001–02 season was the 87th season of the Isthmian League, which is an English football competition featuring semi-professional and amateur clubs from London, East and South East England. The league consisted of four divisions for the last season. At the end of it single Division One was divided into Division One North and Division One South, most of the clubs in Division Two were promoted to the newly created divisions. Division Three was disbanded after all the clubs were promoted to divisions One North, One South and to Division Two.
Gravesend & Northfleet won the division and were promoted to the Football Conference. Canvey Island finished second for a second season in a row. At the end of the season the Premier Division was expanded up to 24 clubs, so only one club were to relegate this season.
League table
Division One
Division One consisted of 22 clubs, including 16 clubs from the previous season and six new clubs: Three clubs relegated from the Premier Division:
At the end of the previous season Barking ceased to exist when they merged with East Ham United to form Barking & East Ham United, taken place of Barking in Division One. Ford United won the division and were promoted to the Premier Division along with Bishop's Stortford and Aylesbury United. At the end of the season Division One was replaced by divisions One North and South, remaining clubs were distributed between newly created divisions. There was no relegation from Division One this season.
League table
Division Two
Division Two consisted of 22 clubs, including 16 clubs from the previous season and six new clubs: Three clubs relegated from Division One:
Lewes won the division at the first attempt. At the end of the season most of Division Two clubs were transferred to the newly created divisions One. Their places were taken by clubs from disbanded Division Three.
League table
Division Three
Division Three consisted of 22 clubs, including 19 clubs from the previous season and three clubs relegated from Division Two:
Croydon Athletic won the division and were promoted two tiers up along with eight other clubs. At the end of the season Division Three was disbanded due to creation of divisions One, clubs were distributed between newly created divisions.
