Konstantinou kai Elenis (Greek: Κωνσταντίνου και Ελένης; English: Konstantino's and Eleni's) is a Greek TV sitcom broadcast on ANT1 channel, which aired from October 1998 until June 2000. The story revolves around the cohabitation of two people with very different personalities; an assistant professor of Byzantine Studies at the University of Athens named Konstantinos Katakouzinos and a waitress named Eleni Vlachaki. The series focuses on the clash of Konstaninos and Eleni's very different personalities as they live together and have to deal with each other.

The main stars are Haris Romas, who co-wrote the script along with Anna Hatzisofia, and Eleni Rantou. The character of Manthos is portrayed by Vasilis Koukouras whereas the character of Peggy, Matina and Nikolas are portrayed by Maria Lekaki, Kalirroi Miriagou and Stergios Nenes respectively. The series ran for two seasons, 1998-1999 and 1999-2000, and consisted of 68 episodes. Each episode lasts about 40–45 minutes. Reruns of the series are still being broadcast to date.

Konstantinou kai Elenis is widely considered the most successful Greek TV series of all time and maintains a huge cultural impact on the Greek-speaking world even to this day. The show is also one of the few Greek-produced that have achieved a cult status, scoring high viewership ratings for roughly twenty years after its finale and maintaining a dedicated fanbase.