This section covers teams that competed in the second tier of Division I since it was split in 1978: Note that Division I FCS features a single-elimination championship tournament, reducing the likelihood of multiple teams finishing the season with undefeated records.
However, several conferences voluntarily do not compete in the tournament, thus there exists a chance to have multiple undefeated teams in the same year.
In both lists in this section, teams in bold competed in the I-AA or FCS playoffs, thereby winning the national title.
These teams finished the season with no losses or ties in Division I-AA or FCS football since 1978.
[104] These teams finished the season with no losses, but with ties, in Division I-AA or FCS football since 1978.