Luton have signed Huddersfield Town left-back Jack Senior on a two-year deal and Newcastle midfielder Alex Gilliead on loan until 7 January.
Senior, 19, has signed for undisclosed terms after failing to make a first-team appearance for the Terriers.
Gilliead spent last season on loan with League Two side Carlisle, scoring five goals in 41 appearances.
One of the 20-year-old's goals came in the Cumbrians' 4-3 win over the Hatters at Kenilworth Road in November 2015.
"Coming from Newcastle and the north-east and moving south, it's a big move for me, a new challenge," he told the club website.