Štvrtok na Ostrove (Hungarian: Csallóközcsütörtök, pronounced [ˈtʃɒlːoːkøztʃytørtøk], formerly Csütörtök) is a village and municipality in the Dunajská Streda District in the Trnava Region of south-west Slovakia.

The earliest extant document about the village dates back to 1217, in which it was referred to it by its Hungarian name as Villa Ceturthuc.

The village enjoyed Royal privilege to collect tolls and in the fifteenth century it gained the status of a town and had the right to hold markets and develop crafts and trades.

Until the end of World War I, it was part of Hungary and fell within the Somorja district of Pozsony County.

After Soviet occupation in 1945, Czechoslovak administration returned and the village became officially part of Czechoslovakia in 1947.