"It seems reasonable therefore not to deploy Vista until it has a demonstrably stable and secure track record," the report states.
Most of the 25,000 schools in UK schools contract to use Microsoft products, representing about 2 million computers.
"We need to see a persuasive business case for the level of investment needed to deploy the products," said Tom McMullan, a consultant for BECTA. "What we are saying in the short term is that the case has not been made."
The report found that 27% of Vista's added features were available without upgrading from XP, such as the new Internet Explorer 7 browser and Windows Media Player, both of which can be downloaded free from Microsof.
Of 176 new features identified in Office 2007, none were "must-have" for education institutions, and most are aimed at businesses, the study said.
"Clearly, we would like to think it could have been better," said Steve Beswick, Microsoft's director of education in the U.K."We feel very confident that once customers see the technology and evaluate it correctly, upgrades will happen."