Toffolo has also been fined more than £20,000.
Toffolo was charged in July.
The 28-year-old is alleged to have committed the offenses between January 2014 and March 2017 when he was on the books of Norwich City.
Toffolo also spent time on loan at Swindon Town, Rotherham and Scunthorpe during the stipulated period.
The Englishman made 19 Premier League appearances last season as Nottingham retained their top flight status.
His only appearance this season however has come in the Carabao Cup against Burnley.
An FA spokesperson said: “Nottingham Forest’s Harry Toffolo has been given a five-month suspension, which has been suspended until the end of the 2024/25 season, and £20,956.22 fine for misconduct in relation to our betting rules.
“The defender admitted that he breached FA Rule E1(b) 375 times between 22 January 2014 and 18 March 2017, and an independent Regulatory Commission imposed his sanctions following a hearing.
“The Regulatory Commission’s written reasons for these decision will be published in due course.”
Back in May, Brentford striker Ivan Toney was banned for eight months after he admitted to breaching the FA's betting rules 232 times over a four-year period.
Unlike Toney, the suspended nature of Toffolo's ban means he will still be available for selection.
