The leaders of the 19 most powerful countries in the world, the European Union and seven other guest countries have gathered in Osaka, Japan to discuss a range of international issues.
Between them they represent more than 80% of global GDP and will be talking about global economy, trade and investment, innovation, environment and energy, employment, women’s empowerment, development and health.
Here is what could be, the most interesting discussions that will take place in Osaka:
Britain’s relationship with Russia
Ms May will be meeting with Russian President Vladimir Putin. The two countries have had a fraught relationship after Britain blamed Russia for poisoning former Russian spy Sergei Skripal and his daughter Yulia in Salisbury.
While the Kremlin has said the meeting was intended to help improve relations between the two counties, Downing Street said it did not represent a normalisation of the relationship.
Ms May’s spokesperson said her position about Russia’s pattern of “malign behaviour” was well known and she would “deliver this message” to Mr Putin.
Even before arriving in Japan Donald Trump tweeted that he would be talking to Indian Prime Minister Narendra Modi about their “very high tariffs”.
Mr Trump is apparently unhappy that India has just introduced tariffs on 28 US products, including almonds and apples.
Some of the tariffs are as high as 70% and are in retaliation to the US refusing to exempt India from the steel and aluminium imports they introduced.
China is apparently considering presenting a proposed settlement to end their trade war with the US, according to the Wall Street Journal.
US relations with its allies
Donald Trump gave an explosive interview with Fox Business before he left for Japan.
During the interview he criticised the EU for introducing antitrust cases against US technology companies and he questioned the decades-long US-Japan security alliance.
The Japanese leader, Shinzo Abe, who is essentially the host of the entire summit, is unlikely to be impressed with Mr Trump’s comments.
Ms May has called for “de-escalation” and other European leaders have raised concerns about a US-Iran conflict destabilising the Middle East.
As a long-standing ally of Iran, China’s contribution to the discussions about the tension in the Middle East is likely to be an interesting affair.