| En Name: | Serpeysk |
| Ru Name: | Серпейск |
| Image Coa: | Serpeysk COA (Kaluga Governorate) (1842).png |
| Coordinates: | 54.3353°N 34.9889°W |
| Pushpin Map: | Russia Kaluga Oblast#European Russia#Russia |
| Federal Subject: | Kaluga Oblast |
| Adm District Jur: | Meshchovsky District |
| Inhabloc Cat: | Rural locality |
| Pop 2010Census: | 658 |
| Established Date: | 1406 |
| Established Title: | First mentioned |
Serpeysk (Russian: Серпейск; Polish: Sierpiejsk) is a village (selo) in Meshchovsky District of Kaluga Oblast, Russia, located on the Serpeyka River.
The locality has a canting arms, depicting two sickles, with Russian: link=no|серп, Polish: link=no|sierp meaning sickle.
It was first noted in 1406 as a military fort of the Grand Duchy of Lithuania on its border with Muscovy. Later on, it was annexed to Muscovy by Ivan III of Russia, then recaptured by the Polish–Lithuanian Commonwealth,[1] and eventually incorporated into Muscovite Russia after the signing of Treaty of Polyanovka which marked the end of the Smolensk War in 1634. Once stripped of its garrison, the town dwindled into oblivion. The oldest surviving buildings are two churches, one dating from 1771 and the other constructed in the 1780s. In the late 19th century, it had a population of 1,818.[1]