The G20 summit in Argentina is the first major international event Prince Mohammed has attended since the murder of the Washington Post columnist, a critic of the crown prince, in the Saudi consulate in Istanbul in October.
"I am going to speak to the crown prince of Saudi Arabia but it is the relationship we have with Saudi Arabia that enables me to sit down with him and be robust on our views on two issues," May told Sky News in an interview on Friday.
She said she would tell him that the investigation into Khashoggi's killing must be full and credible and that those responsible must be held to account.
Asked whether she would specifically challenge him about reports of his involvement in the killing, a senior British official said the focus of the discussion would be about concluding the investigation as soon as possible.
May is keen not to alienate allies around the world as Britain prepares to leaves the European Union next year in its biggest foreign and trade policy shift in more than 40 years.
French President Emmanuel Macron told the crown prince earlier on Friday that Europe would insist on international experts being part of the investigation into the murder of Khashoggi.
The British official said May was not expected to discuss trade with the Saudi crown prince.
May will also meet with Turkish President Tayyip Erdogan on Saturday, the official said, with discussion likely to include Turkey's investigation into the killing.
May said she would encourage the Saudis to find a political solution to the situation in Yemen. Western nations are calling for an end to the Saudi-led military campaign, launched by Prince Mohammed, as a humanitarian crisis there worsens.
"We believe that now is the time. There is an opportunity to find a solution, to come to a political solution because that is the way to ensure the future and a safe and secure future for the people of the Yemen," she said.
Britain has come under pressure to cease arms sales to Saudi Arabia because of the high death toll in air raids by the Western-backed Saudi-led coalition in Yemen. (Reporting by Kylie MacLellan, writing by Sarah Young; editing by Guy Faulconbridge and Hugh Lawson)
(This story has not been edited by Devdiscourse staff and is auto-generated from a syndicated feed.)