Kallieis is a former municipality in the northern part of Phocis, Greece. Since the 2011 local government reform it is part of the municipality Delphi, of which it is a municipal unit. The municipal unit has an area of 183.256 km2. Its registered population in 2021 amounted to 1,123. The seat of the municipality was Mavrolithari, which is home to about 10% of the municipal unit population. The municipality was named after the ancient people of Kallieis, a Dryopean tribe.