In an 8–1 decision, Justice Lewis Powell wrote for the majority, that "through its policy of accommodating their meetings, the University [had] created a forum generally open for use by student groups."

In this case, the University asserted an interest in fulfilling its responsibilities under the Establishment Clause of the First Amendment.

But Powell argues that a regulation opening facilities to both religious and secular groups would pass the three-pronged test established in Lemon v. Kurtzman (1971).

Justice Stevens concurred in the Court's opinion, but wrote a concurrence to note a minor disagreement about whether or not the situation even amounted to a "forum".

In 1984, Congress passed a law, the Equal Access Act of 1984, which extended the effect of the Court's opinion in Widmar to all secondary schools that receive federal education funds.