Roccalbegna is home to several notable fortifications, such as the Cassero Senese (built in the 13th century by the Aldobrandeschi, renovated in the 15th century) and the Rocca Aldobrandesca, located on the hill overlooking the town and the Albegna river (whence the town's name). Outside the town there is the large Castello di Triana (known from 760), also owned by the Aldobrandeschi and then by the Sforza of Santa Fiora; it has maintained its medieval line of walls. The hamlet of Cana has also an Aldobrandeschi-built line of walls from the 13th century.
Also notable is the Romanesque-Gothic church of Santi Pietro e Paolo (13th-14th centuries, modified in the 18th century). It has a large Gothic portal surmounted by a rose window. It houses some parts of a polyptych by Ambrogio Lorenzetti (c. 1340), a Pietà by Alessandro Casolani and a 15th-century small fresc of Madonna with Saints.