Associazione Calcio Siena (often referred to as ‘Robur’ or simply ‘Siena’) is an Italian football club based in Siena.

The club currently plays in Serie A, having gained promotion from Serie B at the end of the 2010-2011 season.

The club plays its home games at the Stadio Artemio Franchi. The ground’s capacity is only 15,725 and is located in Siena itself, whereas its more famous namesake is located in Florence.

In March 2011, A.C. Siena announced plans to move to a new stadium at Isola d’Arbia, at the southern end of the city. The 20,000 seat stadium features a unique below-ground design and was awarded an MIPIM AR Future Projects Award for 2011.

The team’s home colours are white and black.