Roy led the Kitchener Rangers of the Ontario Hockey League (OHL) with 87 points during the 1999–2000 season, and won the OHL Rookie of the Year trophy. The next season, he scored 42 goals and 81 points whereupon he was drafted 32nd overall by the Buffalo Sabres in the 2001 NHL Entry Draft at the end of the season. The next season, 2001–02 Roy set his OHL career highs of 43 goals and 89 points and continued to be the Rangers' leading scorer.