Politicians on both sides of the Brexit debate must attempt to treat other with respect in a bid to avoid a "divisive Brexit", Ruth Davidson will warn on Monday evening (5 December).
The Scottish Conservative leader will urge Leave and Remain campaigners to heal their divisions and drop accusations of racism on one side or "remoaning" on the other.
"Our decision to leave the European Union hasn't determined which path we'll take. That's a decision we'll make as a nation," she will say.
"And one indicator is how we carry ourselves as we proceed in the months ahead.
"And to ensure we choose the path of openness and engagement, above all, I believe we must do all we can to avoid an unnecessarily divisive Brexit.
"That starts with coming back together and healing the divisions here at home that the referendum campaign has caused."
Davidson will add: "And if healing the divisions starts at home, it must also be carried on with the way we conduct ourselves internationally.
"Theresa May has already made it clear she wants to choose the path of openness. That is right and it is vital."
She will issue the plea as she delivers the Rhondda lecture, named after suffragette Viscountess Rhondda, at business body the Institute of Directors (IoD).
Davidson, who campaigned for Remain, will also attack Ukip for "rubbing Europe's noses" in the EU referendum result.
"So I say to those Ukip politicians: when they chuckle and bray about the result in June and how they've taught Europe a lesson - grow up," she will say.
"Let's show a bit more respect for our European neighbours, and allies, please. We should do that for its own sake, because it is the right thing to do.
"But even, if that is beyond their understanding, we should do it for reasons of self-interest too.
"Our UK government is going to have to sit down very soon with 27 other EU member states and find a way forward."
The comments will come just hours after the UK government launched its appeal at the Supreme Court over Article 50, the official mechanism to split from the EU.
England's High Court had dealt May and her ministers a blow by ruling that MPs should have a vote on the issue.
The government had unsuccessfully argued that ministers had the legal authority – residual prerogative powers – to trigger Article 50 without giving parliament a vote.
May has promised the British electorate and EU leaders that she would start formal Brexit negotiations by March 2017. That process could be delayed if the Supreme Court rejects the government's appeal.