Markopoulo Mesogaias (Greek: Μαρκόπουλο Μεσογαίας) is a town and a municipality in East Attica, Greece.

Greek National Road 89 (Gerakas - Koropi - Lavrio - Sounio) passes through Markopoulo.

Markopoulo along with Malakasa, Kakosalesi and Spata is one of the earliest villages formed by Albanian settlers in medieval Attica and it had already appeared by 1456.

Today, tourism is a major driver as the nearby seaside town, Porto Rafti, is a very popular tourist destination in Attica.

Multiple companies, including SkyGreece Airlines have had their corporate headquarters in Markopoulo Mesogaias due to the easy access to Athens International Airport.