Deni Avdija (born 3 January 2001) is an Israeli–Serbian professional basketball player for the Washington Wizards of the National Basketball Association (NBA). He plays the small forward position.

The son of basketball player Zufer Avdija, he joined Maccabi Tel Aviv in 2013 and excelled as a youth player. He debuted for their senior team in 2017, at age 16, becoming the youngest in club history. Two years later, he became the youngest player to ever win the Israeli League Most Valuable Player (MVP) award and led his team to the Israeli League championship.

In 2020, Avdija declared for the NBA draft, joining the Washington Wizards.

Avdija is also a member of the Israeli senior national team. He has won two gold medals for Israel at the youth level, including at the 2019 FIBA U20 European Championship, where he was named tournament MVP.