How Often Do Underdogs Win In the NCAA Tournament?

March Madness is one of the most popular sporting events in North America, with millions tuning in to watch the Field of 68 whittle its way down to one national champion. 

The NCAA Tournament is one of the only sports events that regularly converts non-bettors into bettors. Whether or not it’s a $5 office pool or a traditional bet in something like the college basketball odds market, people love to stake their own personal March Madness predictions.

Since I’m the resident college basketball expert here at the BetMGM blog, I thought I’d wade into the data to provide a definitive answer on a routine March question: How often do tournament underdogs actually win?

How Often Do College Basketball Underdogs Win in the NCAA Men’s Basketball Tournament?

Since 2018, when the U.S. Supreme Court overturned PASPA, underdogs have won their NCAA Tournament games about 30% of the time. 

Underdogs are 122-279 (30.4%) straight up since the 2019 NCAA Tournament. 

So Does That Mean Underdogs Are a Good Bet In the NCAA Tournament?

As with most things in life… it depends.

The ROI on blind betting every underdog since 2019 is -4.9%. If you bet $100 on every underdog, every game, you’d be down roughly $2,000.

But of course, most people don’t bet on underdogs with such an obtusely wide strategy. Bettors who use a little bit of discernment in picking underdogs can quickly reap a profit.

But there’s another important caveat with these numbers too, and that’s the strong effect of the 2025 NCAA Tournament.

March Madness was famously chalky in 2025. It was one of only two seasons since the 1980s where all four No. 1 seeds advanced to the Final Four. Favorites went 53-14 straight up. Upsets were few and far between.

It was a really, really bad year to bet dog moneylines. And if you remove the 2025 games from the sample of the last six tournaments, the remaining dataset of 2019-24 is suddenly much more friendly to blind-betting underdogs. 

Underdogs still won only one about one in three games, but the ROI flips to +3.2%. 

If you also remove the 2019 tournament – another historically rough year for underdogs – the ROI explodes to +12%. 

So, yes, betting dogs to win in the NCAA Tournament is generally a good strategy. At minimum, if you like an underdog to cover in March, you should probably consider supplementing with some moneyline exposure, too.