Wisconsin is No. 9.
Vanderbilt improved to 4-0 for the second time in four seasons, but just the fourth time since World War II, with a 23-17 win at Mississippi on Saturday.
Vanderbilt is the only private school in the SEC and the smallest by student body.
Two more teams from non-BCS conferences crashed the gates, too. No. 24 TCU was ranked for the first time this year and No. 19 Boise State won at Oregon 37-32 to make it in.
No. 11 BYU is one of three Mountain West Conference teams in the latest Top 25, a first for that league, along with No. 17 Utah and TCU.
The Western Athletic Conference has two teams in the rankings — Boise and Fresno State, which stayed at No. 25 after going to double overtime to beat Toledo 55-54.