Agiorgitiko (Greek: Αγιωργίτικο; also known as Aghiorghitiko) is a red Greek wine grape variety that, as of 2012, was the most widely planted red grape variety in Greece, ahead of Xynomavro. The grape has traditionally been grown in the Nemea region of the Peloponnese but can be found throughout the country including Attikí (Attica) and Makedonía (Macedonia).

One of the more commercially important indigenous Greek varieties, it can exhibit a wide range of characteristics, from soft to very tannic, depending on factors in the growing and winemaking processes. The grape is typically made as a varietal, though it is notably blended with Cabernet Sauvignon in the area around Metsovo to make the table wine traditionally called katoi. In the region of Nemea it is often made into rosés of oak-aged red wines. The wines are known for their high level of fruitiness but tend to lack some acidity and body.

The red wine produced from the grape is characteristically spicy with notes of plum. It has low acidity but good fruitiness and coloring.

Agiorgitiko is generally planted in dry, infertile soil to encourage the production of fewer but more concentrated grapes, ripening after mid-September.

Ampelographers believe that Agiorgitiko is indigenous to Greece, likely the Argolis and Corinthia regions of Peloponnese, but while apocryphal tales exist of the grape being cultivated in Ancient Greece, there is no historical or genetic evidence to support those tales. In Nemea, the wine made from Agiorgitiko is nicknamed the "Blood of Hercules" because of the legend that after the Greek hero slayed the Nemean lion, it was the local Nemean wine made from Agiorgitiko that he consumed. (Some versions of the story has Hercules consuming the wine before slaying the lion.) Another legend states that the wine was a palace favorite of king Agamemnon who led the Greek forces during the Trojan War.

The name Agiorgitiko means literally "St. George's grape" which could be a reference to the chapel of Saint George in Nemea or to Saint George's Day which is celebrated in November around harvest time in some Eastern Orthodox Churches. However, in many of the Greek areas where Agiorgitiko is grown, Saint George's Day is celebrated in April or May which cast doubt on the theory that the grape's name is affiliated with the feast day. Another theory is that the grape is named after one of the many Greek towns named after the Christian saint.

The main land owners in Nemea was the church and the monks from St George monastery of Feneos would tend to the vineyards and harvest the grapes to make wine at the monastery for communion. This is another theory of the naming of the St George wine is after the St George monastery of Feneos.

Agiorgitiko tends to produce small clusters of small, thick-skinned berries. The vine is highly disease prone with Master of Wine Jancis Robinson noting that "virtually all Agiorgitiko vines planted in Greece are virused." Depending on the virus, and age of the vine, this can lead to issues with ripeness and yields which can affect the resulting quality of the wine.