Neil, 36, has spent his entire NHL career with the Senators since they selected him in the sixth round of the 1998 draft. He has 109 goals and 134 assists in 956 games for Ottawa.
The gritty tough guy is an alternate captain and popular teammate. General manager Bryan Murray called Neil "someone who exemplifies strong work ethic and character while striving to be a leader and a good example for our young players."
Murray added that it would only be fitting for Neil to hit the 1,000-game milestone in a Senators uniform next season.