The 1999–2000 Northern Football League season was the 102nd in the history of Northern Football League, a football competition in England.
[1] Division One featured 17 clubs which competed in the division last season, along with three new clubs, promoted from Division Two: Also, Stockton changed name to Thornaby-On-Tees.
Division Two featured 16 clubs which competed in the division last season, along with three new clubs, relegated from Division One: Also, Ryhope CA changed name to Kennek Ryhope CA, while Washington changed name to Washington Ikeda Hoover.