Sunday's findings by UNICEF are based on responses from hundreds of families among Jordan's 660,000 registered refugees, AP reported.
Some 5.5 million Syrians have fled civil war in their homeland since 2011, most settling in neighboring countries where they struggle to survive.
Robert Jenkins, the agency's Jordan representative, says the findings show that refugee children "are facing a more challenging time in meeting their minimum basic needs."
He called on donor countries to step up at a time of growing need.
UNICEF in Jordan lacks $145.7 million for child programs in 2018.