The Football Conference season of 1990–91 (known as the GM Vauxhall Conference for sponsorship reasons) was the twelfth season of the Football Conference.
Barnet finished the season as Conference champions and were promoted to the Football League Fourth Division, finishing narrowly ahead of Colchester United, who had been relegated to the Conference a year earlier.
There was no relegation from the Fourth Division to the Conference this year, due to expansion of the Football League.