It stopped short of ordering a cease-fire as requested by South Africa.
"The court is acutely aware of the extent of the human tragedy that is unfolding in the region and is deeply concerned about the continuing loss of life and human suffering," Court President Joan Donoghue, who read the court's ruling, said.
The judge said that, in the court's view, at least some of Israel's actions in Gaza brought forward by South Africa fell within the provisions of the UN's Genocide Convention.
Donoghue said the court could not "accede to Israel's request that the case be removed from the general list."
What was the court asked to decide?
The Hague-based court was asked to rule on nine measures, including an order compelling Israel to suspend its military operations in Gaza.
The ruling did not deal with South Africa's core accusation in the case as to whether Israel is committing genocide in the Palestinian enclave. Instead, the measures sought by South Africa were intended to "protect against further... harm to the rights of the Palestinian people" under the Genocide Convention.
The provisional measures requested by South Africa were essentially requests to be put in place before a final ruling on the main case, which could take years.
While the ICJ's rulings are binding on all parties, it has no mechanism to enforce them.
What was the response to the court's decision?
After the ruling, South Africa's Minister of International Relations, Naledi Pandor, called on Israel to implement the court's orders.
"If Israel acts in accordance with, I think the implications are for future hopeful world. Should it not, then essentially we're opening up room for all abusers in many conflicts around the world, and I think we'll be setting a terrible, terrible precedent," she said.
Israeli Prime Minister Benjamin Netanyahu responded, denouncing the genocide case as "outrageous" and saying Israel would continue to do "what is necessary" to defend itself.
"Israel's commitment to international law is unwavering. Equally unwavering is our sacred commitment to continue to defend our country and defend our people. Like every country, Israel has an inherent right to defend itself," he said.
Palestinian Foreign Minister Riyad al-Maliki called on all states to ensure that all the measures ordered by the court are implemented.
"The ICJ order is an important reminder that no state is above the law. It should serve as a wake-up call for Israel and actors who enabled its entrenched impunity," he said.
What has the court heard so far?
South Africa has contended that Israel's actions have breached the United Nations Genocide Convention and that they were intended to "bring about the destruction of a substantial part of the Palestinian national, racial and ethnical group."
"The acts in question include killing Palestinians in Gaza, causing them serious bodily and mental harm, and inflicting on them conditions of life calculated to bring about their physical destruction," South Africa's writ says. "The acts are all attributable to Israel, which has failed to prevent genocide and is committing genocide in manifest violation of the Genocide Convention."
Israel's lawyer Tal Becker has dismissed the South African case as a "profoundly distorted factual and legal picture" and a "decontextualized and manipulative description of the reality."
Becker showed the court images of the brutal Hamas terror attack of October 7 and said that "if there have been acts that may be characterized as genocidal, then they have been perpetrated against Israel."
The lawyer denied that Israel's operations were aimed at Gaza's citizens. He said the army's aim was "not to destroy a people, but to protect a people, its people, who are under attack on multiple fronts."
Israel has vowed to eradicate the Islamist movement Hamas after the attacks that left about 1,140 people dead in Israel.
The Israeli military has launched an offensive in Gaza that the Palestinian territory's Hamas-run health ministry says has killed at least 25,900 people.
Israel's strongest ally the United States has opposed South Africa's case, while some European Union members and Britain have refused to support it.
The ICJ, also called the World Court, is the only international court that adjudicates general disputes between nations.