US Ambassador to Lebanon Elizabeth H Richard told reporters at Beirut's port that the latest assistance is in "an entire ship full of military equipment."
A US Embassy statement said the shipment includes 50 armored Humvees, 40 Howitzers and over 1,000 tons of ammunition.
The US has been speeding up delivery of ammunition to help Lebanon's military combat jihadi groups near the border with Syria.
In March, Washington delivered three Huey II helicopters, raising to 10 the number of such US-made aircraft in Lebanon's fleet