Last month, Khartoum argued before the UN's top court that the UAE was violating the Genocide Convention by supplying weapons to paramilitary forces.
The judges sided with the UAE in its ruling, accepting its arguments that the UN court "manifestly lacked" jurisdiction to rule on the case.
Sudan had made a request to the court for urgent measures against the Gulf nation.
However, the UAE had firmly argued that the court was not legally competent to rule on the matter.
When the UAE signed up to the UN's Genocide Convention in 2005, it entered a "reservation" to a key clause allowing one country to sue another at the ICJ over disputes.
This reservation meant the Hague-based ICJ had no power to intervene in the case, the Emiratis said.
While the top UN court agreed with this, it expressed its concern about violence in the region.
The ICJ said it was "deeply concerned about the unfolding human tragedy in Sudan that forms the backdrop to the present dispute.".
"The violent conflict has a devastating effect, resulting in untold loss of life and suffering, in particular in West Darfur," the court added.
In their ruling, the judges added that, regardless of the opt-out clause, states "remain responsible for acts attributable to them which are contrary to their international obligations.".
Since April 2023, Sudan has been plunged into chaos by a brutal power struggle between army chief Abdel Fattah al-Burhan and paramilitary RSF commander Mohamed Hamdan Daglo.
The conflict has sparked what aid agencies now call the world’s worst displacement and hunger crisis, with famine officially declared in five regions, according to a UN-backed report.
