Namayan was an independent indigenous: 193 polity on the banks of the Pasig River in the Philippines. It is believed to have achieved its peak in 1175, and to have gone into decline some time in the 13th century, although it continued to be inhabited until the arrival of European colonizers in the 1570s.

Formed by a confederation of barangays, it was one of several polities on the Pasig River just prior to the Spanish colonization of the Philippines, alongside Tondo, Maynila, and Cainta.Archeological findings in Santa Ana, Namayan's former seat of power, have produced the oldest evidence of continuous habitation among the Pasig river polities, pre-dating artifacts found within the historical sites of Maynila and Tondo.