Konstantinos "Kostas" Papanikolaou (Greek: Κωνσταντίνος "Κώστας" Παπανικολάου; born July 31, 1990) is a Greek professional basketball player for Olympiacos of the Greek Basket League and the EuroLeague. Standing at 2.04 m (6'8 ⁄2") tall, he plays at the small forward position. He has previously played in the NBA for the Houston Rockets and Denver Nuggets, and is also a member of the senior Greek national team.
Papanikolaou began playing basketball with the youth teams of Proteas Grevenon and Aris, and he made his pro debut in the Greek League, with Aris, during the 2008–09 season. He was named the MVP of the Greek Youth All-Star Game in 2009. He was also named the Greek League's Best Young Player in 2009.
On September 14, 2009, Papanikolaou signed a five-year, €1.3 million net income deal with Olympiacos, after Olympiacos paid a €950,000 buyout fee to Aris, to secure his player rights. Papanikolaou's contract with Olympiacos had an NBA buyout clause worth €1 million.