The Oxford-based rider, who has ridden under the guidance of Alberto Puig at Repsol Honda for the past two seasons, has signed a contract to ride for the Polaris World team - which has won four grands prix, and taken nine pole positions, with Mattia Pasini this season.
Smith will ride one of the latest factory Aprilia machines, which have won 13 of the 16 rounds held so far this year.
"I'm very proud to have been made such a brilliant offer and already I'm looking forward to next season," said Smith. "To compete on a slightly more competitive machine with the support of such a professional team will be fantastic. In the meantime I will now concentrate all my efforts at the final grand prix of the season in Valencia, Spain a week on Sunday."
Smith, who currently lies tenth in the 125cc World Championship with one round remaining, re-wrote the history books earlier this year when he finished third in the French Grand Prix at Le Mans - making him the youngest British rider to finish on a grand prix podium in the 58-year history of world championship racing.
