Siena are at the bottom of the Serie A and youth coach marco Baroni will replace Giampaolo.
A club statement read: “Siena announces it has dismissed Marco Giampaolo as head coach of the first team.
“The club wishes to thank Marco and his assistants for the work done up to now and wishes them the best of luck.
“Marco Baroni will guide the team and will be in charge of today’s training session.”
