Wilson has only made one Carling Cup appearance for the Shrimpers this season, and does not feature in the immediate plans of manager Steve Tilson.
"He has not played this season so it's good for both parties for him to go out on loan," said Tilson.
"I can't fault his attitude in training when he has not been playing, hopefully he can help Brentford stay up."
The Bees are firmly rooted in the bottom four of League One, but were boosted by Saturday's battling draw at relegation rivals Leyton Orient.