About 100 Ukrainian troops will head to the US soon to begin training on the Patriot missile defence system, two American officials said.
Ukraine has long sought the Patriot surface-to-air guided missile defence system because it can target aircraft, cruise missiles and shorter-range ballistic missiles.
During his late December visit to the US, Ukrainian President Volodymyr Zelensky said the battery would make a significant difference in bolstering Kyiv's defences against Russia's invasion.
The number of Ukrainians coming to Fort Sill in Oklahoma is approximately the number it takes to operate one battery.
Kyiv's decision to take troops off the battlefield to train across the Atlantic in the US is unusual, although it has sent forces for short-term training at European bases for other more complex systems it has received, such as on the longer-range High Mobility Artillery Rocket System (Himars).
The US pledged one Patriot battery in December as part of one of several large military assistance packages it has provided Ukraine in recent weeks.
Last week, Germany pledged an additional Patriot battery.
Each Patriot battery consists of a truck-mounted launching system with eight launchers that can hold up to four missile interceptors each, a ground radar, a control station and a generator.
The US Army said it has 16 Patriot battalions.
The Patriot batteries will complement a variety of air defence systems that both the US and Nato partners have pledged to Ukraine as it faces an evolving barrage of missiles and drones against its civilian population and infrastructure from Russia in the now 11-month old conflict.
In the last few months, Germany has pledged four IRIS-T air defence systems.
The US has also pledged eight mid-range National Advanced Surface-to-Air Missile Systems (Nasams) and Avenger air defence systems.