Perjury would apply to testimony given under oath, which happens at a trial. But most cases don't go to trial, of course. You could also get nailed on "filing a false police report", which is earlier in the process.

But for matters adjudicated by universities, it's possible that neither of these apply, since official police reports are not necessarily filed, and testimony is not given in a courtroom, under oath.

More generally, you could claim defamation. This is not a crime though — it is a civil matter. If the defamer has no assets, it would be an expensive way to make a point ("I didn't do it!") and could lead to the Streisand Effect.

Thanks for breaking that down. Do you think the safeguards (filing a false police report or perjury if in court) are enough? And, if not, do you see any way to implement a law that would not harm sexual abuse victims as a byproduct?

Perjury is a crime against the court. Making a fraudulent claim against a person is a crime against that person.

Appreciate the clarification.