The Defence Secretary says Ukrainian forces have been using Starstreak high-velocity and low-velocity anti-air missiles for more than three weeks.
Ben Wallace told NATO counterparts last month the UK would provide the missile system to Ukraine.
He told the House of Commons on Monday: "I am able to now report to the House that these have been in theatre for over three weeks and have been deployed and used by Ukrainian forces to defend themselves and their territory."
The Defence Secretary added that the UK would also be providing Stormer armoured vehicles to Ukraine to add to their capabilities.
Mr Wallace told the Commons: "As we can see from Ukrainians' requests, more still needs to be done.
"So, for that reason, I can now announce to the House that we shall be gifting a small number of armoured vehicles fitted with launchers for those anti-air missiles," he added.
"The Stormer vehicles will give Ukrainian forces enhanced, short-range anti-air capabilities both day and night."
Watch: Footage recently emerged of Ukrainian troops celebrating after apparently shooting down a Russian drone with a Starstreak launcher and a Martlet missile.
Mr Wallace also gave details of non-lethal aid supplied to Ukraine.
"To date we've sent over 90,000 ration packs, over 10 pallets of medical equipment, more than 3,000 pieces of body armour, nearly 77,000 helmets and 3,000 pairs of boots and much more, including communications equipment and ear defence," he said.
The Defence Secretary said he would not "close off as an opportunity" providing Brimstone missiles as well.
Watch: The Brimstone missile system, explained.
"On Brimstone missiles, we made a commitment I think nearly 18 months ago, two years ago, when we were selling fast-attack patrol boats to Ukraine, that we would sell it armed with maritime Brimstone missiles," the Defence Secretary said.
"We would do that. They are not at present in the country. Those ships have not been yet purchased or delivered.
"However, if we wish to provide Brimstones in whatever guises they are, I will inform members of this House when we do it.
"I don't close it off as an opportunity. I think it’s a perfectly legitimate thing.
"First and foremost, we will look to provide if we do, Brimstone for the land, using stock we already hold but not as yet on the sea."
If you or someone you know needs support at this time, you can find more information here.