The United States and Saudi Arabia have formalised a far-reaching Strategic Defence Agreement (SDA) that includes planned sales of advanced U.S. weaponry and a sweeping investment commitment, marking a pivotal shift in Washington’s engagement with Riyadh.

President Donald Trump and Saudi Arabia’s Crown Prince Mohammed bin Salman signed the agreement during the crown prince’s visit to Washington.

Under the deal, the Kingdom will purchase advanced F-35 stealth fighter jets and nearly three hundred American-made tanks, the White House announced.

The pact also paves the way for U.S. defence firms to have expanded operations in Saudi Arabia and for Riyadh to increase its burden-sharing contributions to regional security.

In concert with the defence accord, the two nations unveiled a dramatic elevation of their economic partnership.

Saudi Arabia committed to raise its investment in U.S. infrastructure, technology and industry to nearly one trillion dollars — building on a prior commitment of six hundred billion dollars earlier this year.

Agreements were announced across civil nuclear energy, artificial intelligence, critical mineral supply chains and capital-markets collaboration.

The agreement also saw Saudi Arabia designated a “major non-North Atlantic Treaty Organization (NATO) ally,” a status that enhances military cooperation and access to U.S. security assistance.

While Washington emphasises that the Kingdom will not receive more advanced technology than Israel to maintain that country’s qualitative military edge, U.S. lawmakers and analysts will scrutinise whether the F-35 sale meets that condition, given Israel’s long-standing reliance on those jets.

Saudi Arabia’s Crown Prince signalled that the security deal remains tied to broader Middle East diplomacy: Riyadh remains cautious on normalisation with Israel, stating its willingness is contingent on progress towards a two-state Palestinian outcome.

For the U.S., the SDA signals a strategic bet that Saudi Arabia will assume a larger role in regional deterrence and defence, while also unlocking American industrial and investment opportunities.

For Saudi Arabia, it marks an assured alignment with Washington at a time of regional fluidity and opens the door to modernising its military and technology base in partnership with U.S. industry.

The deal now enters the implementation phase, during which details of delivery schedules, technology transfer safeguards and congressional export-licensing reviews will be closely watched by allies and adversaries alike.