1999–2000 Gillingham F.C. season

During the 1999–2000 English football season, Gillingham F.C. competed in the Football League Second Division, the third tier of the English football league system. It was the 68th season in which Gillingham competed in the Football League, and the 50th since the club was voted back into the league in 1950. The team started the season in poor form, failing to win any of the first five league games, but then went on a much-improved run and began challenging for promotion to the Football League First Division. Robert Taylor scored 18 goals in 19 games by November, after which he was signed by Manchester City for £1.5 million, a new record fee for Gillingham. On the last day of the regular season, the team had a chance to gain automatic promotion, but lost and instead had to enter the play-offs. After defeating Stoke City in the semi-finals, Gillingham beat Wigan Athletic in the final to gain promotion to the second tier of the English football league system for the first time in the club's history.

Gillingham also had their best run to date in the FA Cup, beating two Premier League teams before being knocked out by a third, Chelsea, at the quarter-final stage. The team reached the second round of the Football League Cup but were eliminated in the first round of the Football League Trophy. The team played 62 competitive matches, winning 34, drawing 12, and losing 16. Despite leaving the club before the mid-point of the season, Taylor was the team's top goalscorer with 18 goals. Nicky Southall made the most appearances, playing 59 times. The highest attendance recorded at the club's home ground, Priestfield Stadium, was 10,386, for the home leg of the play-off semi-final against Stoke City. Having led the team to promotion, manager Peter Taylor left the club after a single season to become manager of Leicester City of the Premier League.