The club have issued a statement on Twitter about their captain, who went down in the first half of the clash with Coventry City at Wembley.
Lockyer did not appear to have anyone around him when he hit the floor, and was tended to quickly by medical staff.
He was eventually stretchered off, and Sky cameras opted against showing any replays of the incident, although videos on social media show that Lockyer appeared to trip over, and then stayed down.
It is unclear exactly why the Luton ace collapsed but the club now say that he is responsive and is with his family in hospital as he undergoes tests.
Writing on Twitter, they said: "We are able to report that after collapsing on the pitch, Tom Lockyer has been taken to hospital for further tests. He is responsive and talking to his family, who are with him. We are all with you, Locks."
Lockyer's collapse happened just 12 minutes into the showpiece to decide which team takes the final promotion spot into the Premier League.
He was replaced by Reece Burke, and Luton will hope that Lockyer makes a speedy recovery if they are able to swat Coventry aside and reach the promised land.
Luton have never played in the Premier League, having been relegated from the First Division in 1991/92, the final season before the formation of the top-flight we know today.