| Agios Konstantinos | |
| Name Local: | Άγιος Κωνσταντίνος |
| Type: | municipal unit |
| Periph: | Central Greece |
| Periphunit: | Phthiotis |
| Pop Municunit: | 2952 |
| Pop Community: | 2786 |
| Population As Of: | 2021 |
| Area Municunit: | 72.29 |
| Coordinates: | 38.75°N 74°W |
| Licence: | ΜΙ |
Agios Konstantinos (Greek, Modern (1453-);: Άγιος Κωνσταντίνος) is a town and former municipality in Phthiotida (Phthiotis), Greece. After the 2011 administrative division reforms it became part of the municipality of Kamena Vourla and it is now ranked as a municipal unit,[1] with an area of 72.292 km2.[2] Its population was 2,952 in 2021.
The town has a harbor with a regular ferry-boat connection to the islands of Skiathos, Skopelos and Alonnisos.[3] These islands are part of the Northern Sporades archipelago.