Russia is not taking part in the the two-day meeting. Kyiv said the delegates would look into a 10-point peace formula pushed by President Volodymyr Zelenskyy.
Saudi Arabia began talks on resolving the Ukraine war on Saturday, Saudi state media reported, despite no delegation from Russia taking part.
Senior officials from some 40 countries including the US, China, South Africa and India are attending the discussions in the Red Sea coastal city of Jeddah.
Ukraine and its allies hope the two-day will lead to an agreement on key principles for a peaceful end to the 17-month conflict and win over non-Western countries that have so far stayed neutral over the conflict due to close ties with Moscow.
Ahead of the summit, aides to Ukrainian President Volodymyr Zelenskyy's said the delegates would look into his 10-point peace plan, which includes Russia withdrawing from Ukrainian territory and returning Crimea to Kyiv's control.
It is not clear whether the talks are aimed at producing a joint statement.
What did Ukraine, Russia say ahead of the talks?
"I predict that the conversation will not be easy, but the truth is on our side," Andriy Yermak, the head of Ukraine's presidential office, said in an interview broadcast on Friday.
"We have many disagreements and we have heard many positions, but it is important that we share our principles," Yermak, who is heading the Ukrainian delegation said. "Our task is to unite the whole world around Ukraine."
In his nightly video message Friday, President Zelenskyy said, "a fair and honest end to Russian aggression will benefit everyone in the world. Everyone!"
Although Russia has not been invited, the Kremlin has said it will keep an eye on the talks.
While the conflict rages, Ukrainian, Russian and international officials say there is no prospect of direct peace talks between the two sides at present.
Saturday's meeting follows Ukraine-organized peace talks in Copenhagen in June that were designed to be informal and did not yield an official statement.
Riyadh hopes to play mediator
Saudi Arabia, the world's biggest crude exporter, works closely with Russia on oil policy but has touted its ties to both sides and positioned itself as a possible mediator in the war.
It has backed UN Security Council resolutions denouncing Russia's invasion as well as its unilateral annexation of territory in eastern Ukraine.
Riyadh also helped mediate a prisoner swap between Ukraine and Russia last year.
Under de facto ruler Crown Prince Mohammed bin Salman, the kingdom has sought a bigger role on the world stage and has pushed to expand ties with major powers outside the old framework of its relationship with the US.
In May, the kingdom hosted Zelenskyy at an Arab summit in Jeddah, where he accused some Arab leaders of turning "a blind eye" to the horrors of Russia's invasion.
Beijing also wants to broker peace
China has also mooted a mediation role for itself in the conflict. Beijing describes itself as a neutral party but Western nations have criticized its close ties with Russia.
In March, Beijing brokered a resumption of ties between Saudi and its arch-regional foe Iran.
Beijing said Friday it would send its special representative for Eurasian affairs, Li Hui, to Jeddah.
Like China, India has maintained close ties with Russia, refused to condemn it for the war and has ramped up imports of Russian oil.