The 24-year-old, who can play on either flank, began his career at West Ham, making 41 Premier League appearances for the Hammers, before heading north to Burnley in 2011.
He made 32 appearances for the Clarets on their way to promotion from the Sky Bet Championship last season yet he rejected the chance to play in the top flight to be reunited with Eddie Howe, who managed him previously at Turf Moor.
Stanislas told the Bournemouth Echo: "Having worked before with the manager, I have always liked what he has done. I always felt confident and comfortable playing for him so wanted to take the opportunity to come here.
"Leaving Burnley was probably the most difficult decision I have had to make so far alongside leaving West Ham to go to there in the first place.
"But over the course of last season, I didn’t play as much as I would have liked. I know it was a successful season for Burnley as a club but, for me individually, working for Eddie Howe and speaking to him about the ambition this club has, I wanted to be a part of it going forward.
"He is very good at getting the best out of players and will always tell you exactly what he is thinking. He will work with you individually on your game and he cares about people. For me, getting the opportunity to work with him again is good."