The 1987–88 season was the 73rd season of the Isthmian League, which is an English football competition featuring semi-professional and amateur clubs from London, East and South East England.
Yeovil Town were champions, winning their first Isthmian League title.
At the end of the season Oxford City left the league after losing its ground.
Before the start of the next season Haringey Borough resigned from the league.
Only Bracknell Town were reprieved from relegation, thus, Division One started next season one club short.