The 2019–20 Frosinone Calcio season is Frosinone Calcio's first season back in second division of the Italian football league, the Serie B, and the 31st as a football club.

Besides the Serie B, the club also competed in the 2019–20 Coppa Italia, losing in the fourth round to Serie A side Parma.

Note: Flags indicate national team as defined under FIFA eligibility rules; some limited exceptions apply.

Players may hold more than one non-FIFA nationality.

Note: Flags indicate national team as defined under FIFA eligibility rules; some limited exceptions apply.