The 26-year-old is the seventh player brought in by Reading manager Brendan Rodgers this summer, as he looks to take the team back to the Premier League.
The manager said: "Brian is a big player at this level. He is a great reference point for the team, he can create and score goals. I've admired him from afar and coming to Reading is the perfect fit for him and his style of play."
Howard spoke of his delight at signing for the Royals. He said: "I'm really happy to sign and now I just can't wait to play. Brendan sold the club to me, his idea of football is the way I want to play the game.
"Hopefully I can bring some goals, my assist and goal ratio has been decent in the past so hopefully I can repeat that here and bring something for the crowd to enjoy."