Sypalettus or Sypalettos () was a deme in ancient Attica of the phyle of Cecropis, sending two delegates to the Athenian Boule.
Probably Sypalettus was a divided deme, even if this hypothesis is not confirmed by all scholars. The inscription that suggests the placement of the deme is a sacred calendar of 470-460 BCE; this document it is very important because it is the first Attican written text that prohibits changes to the law.
Its site is located near Nea Ionia (formerly, Kukuvaones).