Siamamia (meaning "Siam Amia") is an extinct genus of ray-finned fish in the family Amiidae. They are halecomorph fishes endemic to Early Cretaceous freshwater environments from north-eastern Thailand.
Siamamia fossils have been found in the Early Cretaceous Sao Khua Formation, present-day in Phu Phok, Sakhon Nakhon Province, Thailand.