Team B was a competitive analysis exercise commissioned by the Central Intelligence Agency (CIA) to analyze threats the Soviet Union posed to the security of the United States. It was created, in part, due to a 1974 publication by Albert Wohlstetter, who accused the CIA of chronically underestimating Soviet military capability. Years of National Intelligence Estimates (NIE) that were later demonstrated to be very wrong were another motivating factor.

President Gerald Ford began the Team B project in May 1976, inviting a group of outside experts to evaluate classified intelligence on the Soviet Union. Team B, approved by then-Director of Central Intelligence George H. W. Bush, was composed of "outside experts" who attempted to counter the arguments of intelligence officials within the CIA. The intelligence community was in the process of putting together its own assessment at the same time.

Team B concluded that the NIE on the Soviet Union, compiled and produced annually by the CIA, chronically underestimated Soviet military power and misinterpreted Soviet strategic intentions. Its findings were leaked to the press shortly after Jimmy Carter's 1976 presidential election win in an attempt to appeal to staunch anticommunists in both parties and also not to appear partisan. The Team B reports became the intellectual foundation for the idea of "the window of vulnerability" and of the massive arms buildup that began toward the end of the Carter administration and accelerated under President Ronald Reagan.

Some scholars and policy-makers, including Anne Hessing Cahn of the Arms Control and Disarmament Agency, later criticized the Team B project's findings. Many of these experts argued that the findings were grossly inaccurate.