Greek National Road 63 (abbr: EO63) is a national highway in northern Greece. It connects Serres with Promachonas on the Bulgarian border, via Sidirokastro. It is part of the European route E79.
Ministerial Decision G25871 of 9 July 1963 created the EO63 from the old EO43, which existed by royal decree from 1955 until 1963, and followed the same route as the current EO63.