Kansas is the fourth team to hold the No. 1 ranking this season joining North Carolina, Kentucky and Michigan State.
This is the 58th week at No. 1 all-time for the Jayhawks and their first trip to the top since February 2011.
Here's a look at some other tidbits in the AP Top 25 released Monday:
NO. 1 VS. NO. 2:
When Kansas and Oklahoma meet Monday night, it will be the 40th time the top two teams in the poll have played each other. The top-ranked teams have a 21-18 record.
The last time it happened was Nov. 12, 2013, when No. 2 Michigan State beat No. 1 Kentucky 78-74.
This was the 10th time two teams from the same conference met as Nos. 1 and 2 and it's the second time for Oklahoma and Kansas.
RELATED: Full AP Top-25 poll
The last time was when No. 2 Ohio State beat No. 1 Wisconsin 49-48 in Ohio on Feb. 25, 2007, in a Big Ten matchup.
The Atlantic Coast Conference leads with four 1 vs. 2 matchups and North Carolina was in all of them, meeting Duke twice and Georgia Tech and Virginia once each.
The Big Eight, the forerunner of the Big 12 which has Kansas and Oklahoma on Monday night, had two a month apart in 1990 when it was Oklahoma-Kansas and Missouri-Kansas.
The Big East has the other two meetings: St. John's and Georgetown one month apart in 1985.
Four schools moved into the Top 25 this week and three of them are in the poll for the first time this season.
No. 23 Connecticut was ranked in the preseason Top 25 and for the first two weeks of the regular season. The Huskies were then out for two weeks, back in for one and out again for the last two.
Two of the new teams — No. 19 Iowa and No. 25 Dayton — were both ranked for one week last season. No. 24 Pittsburgh was ranked for five weeks in 2013-14.
Cincinnati, which was No. 22, and Baylor, which was No. 23, both dropped out following one loss each last week. Utah, which was No. 21, and UCLA, which was No. 25, both lost two games on their opening weekend of Pac-12 Conference play.
There are three unbeaten Division I teams and they are sprinkled throughout the Top 25.
Oklahoma (12-0) is No. 2, SMU (13-0) is No. 15 and South Carolina (13-0) is No. 22.
Iowa's big week and Xavier's big recoup have them leading the way this season with three wins each over ranked teams.
Iowa, which already had a win over then-No. 20 Wichita State, beat No. 1 Michigan State and No. 14 Purdue last week to earn their first ranking of the season at No. 19.
Xavier, which had already beaten then-No. 24 Michigan and then-No. 23 Cincinnati, rallied from its big loss to Villanova last week by beating No. 9 Butler on Saturday. The Musketeers dropped from No. 6 to ninth this week.
The addition of Pittsburgh gives the Atlantic Coast Conference the most ranked teams at six. Joining the Panthers in the Top 25 are Virginia, North Carolina, Miami, Duke and Louisville.
Three conferences — the Big 12, the Big Ten and the Big East — all have four ranked teams. The Southeastern Conference has three, while the American Athletic Conference has two and the Pac-12 and Atlantic 10 have one each.
In addition to Monday night's 1 vs. 2 matchup between Kansas and Oklahoma the only other game featuring two ranked teams this week is Sunday night's No. 11 Villanova at No. 18 Butler.