The 29-year-old, who has signed a three-year deal with the Spireites, had been available on a free transfer following his departure from Swindon at the end of last season.
"Gary is a quality signing - I don't think there's anybody outside the Premiership who's better on the left wing. The left-hand side has been unbalanced for a long time and the addition of Gary will further strengthen the firepower as he creates and scores goals," Turner told the club's official website.
"Paul Cook has patiently waited for the deal to be done as he has been very keen to bring Gary in. Chairman Dave Allen has provided some great support to ensure the conclusion of the deal."
Roberts has previously represented Huddersfield Town.