The boss alongside assistants Richard O’Kelly and Thomas Frank – have had a year added to their current deals keeping them at the club until the end of the 2018/19 season.
Smith took on the Bees task in November 2015, after Marinus Dijkhuizen failed to live up to the promise invested in him following the contentious departure of Mark Warburton to Rangers.
Former Walsall boss Smith lost just one his first six games in charge, and ended the season in ninth with seven wins out of nine and a3-0 caning for neighbours Fulham.
Bees currently sit a healthy ninth, and ready to reap the benefits of a £15million windfall courtesy of the transfer to Aston Villa of striker Scott Hogan.
Phil Giles and Rasmus Ankersen, Brentford FC Co-Directors of Football, unfolded the reasons for Smith and co’s extension.
Giles said: "It's no secret that 2015 was an up and down year for Brentford, but their arrival helped us to bring some stability and allowed us to concentrate on building some solid foundations for the future.
"In particular, we have reviewed our development model for younger players and continued to build a First Team squad of talented young players on long term contracts.
Rasmus added: “Brentford is a club based on a clear idea about how to do things differently, and Dean and Richard have not only bought into this strategy but also added to it.
“When you take risks to try to gain a competitive edge not all you do will be successful. It is a bumpy road. But it is important to learn from mistakes and stick to what you believe in during tough times.
“Dean and Richard have increased the emotional stability around the training ground which means that no one gets too high when we win and too low when we lose.
“In an industry where emotions often run high both on and off the pitch that is easier said than done.
"But it is something we as a club believe is an absolute key to success in the future, and one of the reasons why we think Dean and Richard can help take us to the next level."
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