That is according to a report on Thursday from data provider WealthInsight and Elite Traveler magazine, which ranked colleges across the world by how many millionaire alumni they had produced.
U.S. colleges dominated the list, with 31 of the top 50 universities producing millionaires.
The U.S.'s University of Pennsylvania ranked second after Harvard and Stanford University ranked third.
"The U.S. has more millionaires than anywhere else in the world, so it is no surprise to see the Ivy League schools on this list," head of WealthInsight, Oliver Williams, said in a news release accompanying the report on Thursday.
University of Pennsylvania
Strictly speaking, Stanford University in California is not part of the Ivy League of top U.S. colleges, but is viewed as academically on a par.
"Since most institutions on this list also rank highly in academic merits, there is evidence here of how intellect often breeds wealth. Entrepreneurial ideas are nursed at these schools, while they prove fertile recruiting grounds for some of the world's leading corporations," Williams said.
England's ancient Oxford University was the top-ranking university outside the U.S., at number four. U.K. rival Cambridge University followed at number 11.
After the U.S., U.K. universities were next best at producing millionaires, with six U.K. colleges making WealthInsight's top 50 rankings.
University of California, Berkeley was the top U.S. public university for producing millionaires and ranked fifth in the world.
University of California, Berkeley
Australia was the best performer after the U.K., with four universities in the list — two in Melbourne and two in Sydney.
"There is a noticeable absence, however, of schools from Asia, which now has nearly as many millionaires as North America. (Asia has 29 percent of all the world's millionaires, whereas North America is home to 33 percent)," Williams noted.
"Such is the international prestige of the Western institutions on this list that many of the newly minted millionaires in Asia were educated in their halls. More still send their children to be educated in Europe and North America rather than at home," he explained.
Research firm Wealth-X has ranked Harvard University as the best college for producing billionaires. Alumni include Michael Bloomberg, CEO of Bloomberg and former New York mayor.
The U.K.'s Institute for Fiscal Studies said on Thursday that despite a big increase in the number of college graduates in the U.K. since the 1960s, the graduate wage premium over those who left school at 16 had held steady.