Royals who are also academics

[PrinceS]

Are there any royal university professors?

[sgl]

HRH Pieter van Vollenhoven of the Netherlands is a professor of risk management at a university in the Netherlands.

I would imagine that there are others, but I don't know for sure.

[acegirl1978]

Thailand's Princess Sirindhorn is a history professor at the Royal Military Academy

[NGalitzine]

I believe the Countess of St Andrews lectures at Cambridge.

[Garthios]

The Emperor of Japan has published his research into Ichthyology, the study of certain types of fish.

Prince Philippe of Belgium was criticised for spending too much time studying at some point, too.

I know that wasn't exactly what you asked for, just a small contribution.

[Charlotte_Aster]

The Countess of Ulster is a physician, she goes by the name Dr Claire Booth while working though.

[Kataryn]

Nikolaus Prince Lobkowicz was president of both the Munich and the Eichstaett univeristies. He is professor since 1960 and today works as director of the Institute for Middle- and East-Europe Studies.