"This resolution is an unnecessary, risky attempt to weaken my constitutional authorities, endangering the lives of American citizens and courageous service members, both today and in the future", Trump said in the veto message.
The resolution, which passed the US House of Representatives earlier this month and the Senate in March, was a historic milestone, as it was the first time in history that a measure invoking the 1973 War Powers Resolution reached the president's desk.
Critics of the Yemen war warn Saudi forces are likely using U.S. weapons to commit atrocities.
"My administration is now accelerating negotiations to end our military engagement in Afghanistan and drawing down troops in Syria, where we recently succeeded in eliminating 100 percent of the ISIS caliphate", Trump said.
Trump added that the resolution is "unnecessary" in part because there are no United States military personnel in Yemen "commanding, participating in, or accompanying military forces of the Saudi-led coalition against the Houthis in hostilities in or affecting Yemen".
He said there were no USA military personnel in Yemen accompanying the coalition fighting Iran-backed Houthis, although he acknowledged that the US had provided limited support to the coalition, including intelligence sharing, logistics support and in-flight the refueling of non-U.S. aircraft. With the resolution, members of Congress were acting on their concerns about the thousands of civilians killed in coalition airstrikes since the conflict began in 2014.
Saudi Arabia and a coalition of Arab governments have launched more than 19,000 air raids across Yemen.
Lawmakers who supported the War Powers resolution called Trump's decision a "painful missed opportunity". The Saudi-led coalition is responsible for the deaths of over 65 percent of those killed, according to United Nations data. Peace in Yemen requires a negotiated settlement. The coalition's bombing campaign-entailing almost 20,000 air raids carried out in part by US bombs sold to Riyadh-has also eroded the country's underdeveloped infrastructure, including ports, markets, hospitals, factories, and roads, which helped prop up the country's faltering economy.
Lawmakers and experts are torn on the impact of Trump vetoing the resolution to cut off US military support in Yemen.
"Houthis, supported by Iran, have used missiles, armed drones and explosive boats to attack civilian and military targets in those coalition countries, including areas frequented by American citizens, such as the airport in Riyadh, Saudi Arabia", Trump said. The UAE is the Saudi Arabia's principal ally in the coalition. "Instead, Trump's veto maintains the status quo and sends a signal to the Yemeni people and parties to the conflict that the U.S.is not willing to use its influence to end this war".