The Battle of Elaia–Kalamas took place in Epirus on 2–8 November 1940. The battle was fought between the Greeks and the Italians during the initial stage of the Greco-Italian War in World War II. The Italian Army, deployed on the Greek-Albanian border, launched an offensive against Greece on 28 October 1940. The main thrust of the Italian invasion occurred in the Epirus sector, with a further flanking move through the Pindus mountains. In Epirus, the Greeks held the Elaia–Kalamas river line, and, even though the Greek army was outnumbered, the local Greek forces under Major General Charalambos Katsimitros stopped the Italian advance. Along with the Italian failure in the Battle of Pindus, these Greek successes signified the complete failure of the Italian invasion, leading to the dismissal of the Italian commander in Albania, Sebastiano Visconti Prasca, on 9 November. In the next few weeks the Greek forces initiated a counteroffensive that forced the Italians to retreat deep into Albania.

The Thyamis, also known as Glykys (Γλυκύς) or Kalamas (Καλαμάς), is a river in the Epirus region of Greece. It flows into the Ionian Sea. It is 115 km (71 mi) long, and its drainage area is about 1,800 km2 (690 sq mi), over 99% of which on Greek territory. The names of the Chameria region, as well as the Chams, derive from the river's name.