Viannos (Greek: Βιάννος) is a municipality in the Heraklion regional unit, Crete, Greece. The municipality has an area of 221.539 km2 (85.537 sq mi). Population 5,563 (2011). The seat of the municipality is in . In September 1943, German occupation forces inflicted heavy loss of life and property on the region of Viannos in reprisal for its support of the Cretan resistance. In late July 2012, the area was hit by wildfires which caused severe damage in crops and livestock.