Puthumana Somayaji (c.1660-1740) was a 15th-century astronomer-mathematician from Kerala, India. He was born into the Puthumana or Puthuvana (in Sanskrit, Nutanagriha or Nuthanvipina) family of Sivapuram (identified as present day Thrissur). The most famous work attributed to Puthumana Somayaji is Karanapaddhati which is a comprehensive treatise on Astronomy.
The period in which Somayaji lived is uncertain. There are several theories in this regard.