Receptors of the Frizzled family transduce important signals during animal development and are conserved from sponges to humans. Frizzled receptors belong to the superfamily of G protein-coupled receptors (GPCRs), but until recently were considered G protein-independent in their signaling. In the present article we review the extensive knowledge demonstrating the functions of trimeric G proteins in Frizzled signal transduction in vertebrates and lower animals. Other structural and functional similarities of Frizzled receptors and the GPCRs are also discussed.