Phthiotis (Greek: Φθιώτιδα, Fthiótida; ancient Greek: Φθιῶτις) is one of the regional units of Greece.
The capital is Lamia city. It is bordered by the Malian Gulf to the east, Boeotia in the south, Aetolia-Acarnania in the southwest, Evrytania in the west and Karditsa regional unit in the north.
The subsoil of the region consists of semi-mountainous, mountainous and lowland areas.The climate is dry in the interior and temperate along the coasts.
The economy of Phthiotis relies on agricultural activities, especially agriculture, farming and logging. Tourism sector in Fthiotis contributes to the local economy as well.
There is a number of thermal springs in Phthiotis which attract a considerable number of tourists. Most famous of all, the sources of Kamena Vourla, Ipatis baths and Thermopyles.