Staff at Oxford University have been told avoiding eye contact with students could constitute "everyday racism".
It is included in a list of "racial micro-aggressions" that has been published in a newsletter by Oxford's equality and diversity unit.
It described micro-aggressions as "subtle, everyday racism" which can be alienating.
Oxford University said the newsletter was one way of supporting its staff in its pursuit of equality of opportunity.
The newsletter said racial micro aggressions might include: "Not making eye contact or speaking directly to people."
Other examples cited were "not believing someone is British", and jokes drawing attention "to someone's difference, their accent, or nationality".
Emeritus professor of sociology at the University of Kent, Prof Frank Furedi, said the newsletter's authors "need a reality check".
"It is almost as if they have become obsessed with the idea that racism is everywhere... and I think what they are doing is trivialising the real meaning of racism."
He added that the unit's interpretation "represents a new expansion of the meaning of racism", and could intensify conflict in an unnecessary way.
The equality and diversity unit's newsletter said micro-aggressions could be "well-meaning", and that people might be "mortified" if they knew they had caused offence.
But it argued this makes little difference if people feel they "do not belong" as a result, and said awareness of "subtle racism" was now included in its training.