Pierogi (Polish pronunciation: [pjɛˈrɔɡʲi]; also spelled perogi, pierogy, perogy, pierógi, pyrohy, pirogi, or pyrogy; diminutive form: Pierożki Polish pronunciation: [pjɛˈrɔʂki] also in use) are dumplings of unleavened dough – first boiled, then they are baked or fried usually in butter with onions – traditionally stuffed with potato filling, sauerkraut, ground meat, cheese, or fruit. Of central and eastern European provenance, they are usually semicircular, but are rectangular or triangular in some cuisines.

The Polish word pierogi is plural; the singular form pieróg is rarely used, as a typical serving consists of several pierogi.

While dumplings as such are found throughout Eurasia, the specific name pierogi, with its Proto-Slavic root "pir" (festivity) and its various cognates in the West and East Slavic languages, shows the name's common Slavic origins, predating the modern nation states and their standardized languages, although in most of these languages the word means pie. In English, the word pierogi and its variants: perogi, pyrogy, perogie, perogy, pirohi, piroghi, pirogi, pirogen, pierogy, pirohy, and pyrohy, are pronounced with a stress on the letter "o". The Turkish word börek for a kind of pie or stuffed pastry may be a borrowing.