The 22-year-old completed the move from Leicester City on Thursday and will be available for the Bees’ Championship match against Birmingham City on Saturday.
Moore previously spent two months with the west London side in early 2013, playing seven games.
England v Germany
U21s international
7.45pm, Monday 30 March
Riverside Stadium, Middlesbrough
Ticket hotline: 0844 499 1234
Buy online: Click here
Since that stint, he has gone on to help Leicester win promotion to the Premier League and has featured regularly for the Foxes in the top flight this campaign.
"Liam is well known to us after his loan two years ago," explained Brentford boss Mark Warburton.
"He has continued his rapid development and established himself with England Under-21s.
"He has also played 11 Premier League games this season - Liam is a very talented young defender."
Speaking to BrentfordFC.co.uk, Warburton added: "Liam will be a welcome addition and adds real competition for places as we enter the final stretch of what has been a good season so far.
"Liam had other options and could have gone to other top six Championship clubs.
"We are delighted he has chosen to join us here at Brentford."
Moore has represented Gareth Southgate’s side on eleven occasions, and was a regular throughout their successful UEFA European Championship qualifying campaign, and will be no doubt in contention to earn a call up for the tournament this summer.
If you want to show your support for Southgate’s side then tickets for the clash on Monday 30 March can be purchased in person at the Boro ticket office or by calling 0844 499 1234. Tickets are also available online.
