Thevally Palace or Thevalli Palace is a popular heritage Palace situated at the banks of Ashtamudi lake, in Thevally, Kollam city. It is an important historic monument in the state of Kerala in India. Thevally Palace was built in between 1811 and 1819 the reign of Gowri Parvati Bayi.

Thevally Palace is a brilliant piece of architecture revealing a perfect fusion of British, Dutch and Portuguese styles of architecture. The majestic building a wonderful sight to the visitors and the rare combination of three styles of architecture distinguish it from other heritage property constructed during the same period. The entire building is made from lime plaster and laterite which delight the viewers coming from far and wide. Within the palace premises, one can also see a beautiful temple dedicated to Lord Sastha.