Semeliškės (Polish: Siemieliszki) is a town in Elektrėnai municipality, Vilnius County, east Lithuania. According to the Lithuanian census of 2011, the town has a population of 580 people. The town has a church of Catholics and Orthodox church of St. Nicolas.
Its alternate names include Sameliškės, Semelishkes, Semelishkis, Semeliškių, Sumelishki, Sumilishki, Siemieliszki, and Sumiliszk.
Memorial at the execution site of the Jews of the town.
On October 6, 1941, 962 Jews of the town were murdered in a mass execution perpetrated by an Einsatzgruppen of local policemen and Lithuanian collaborators.