The All-Ireland Senior B Football Championship was a second tier Gaelic football competition held between 1990 and 2000 and organised by the Gaelic Athletic Association (GAA).

It was contested by county teams who were typically defeated in the early rounds of their provincial championships in the All-Ireland Senior Football Championship.

Designed to improve the standard of football in the so-called "weaker" counties,[1] the competition was held for the last time in 2000, as a result of the introduction of the All-Ireland Qualifiers for the 2001 football championship.

The qualifier system gave each defeated county a second chance via the "back-door", after losing in the provincial championships.

The championship was played on a straight knockout basis, typically starting in October each year alongside the National League fixtures, then concluding in November or December.