Gegard Mousasi (born 1 August 1985), is a Dutch mixed martial artist and former kickboxer currently competing in Bellator MMA where he is the former Bellator Middleweight World Champion. He is also the former DREAM Light Heavyweight Champion, former DREAM Middleweight Champion, former Cage Warriors World Middleweight Champion and the former Strikeforce Light Heavyweight Champion, thus making Mousasi a five-time World Champion. At the moment of his departure from the UFC in July 2017, he was #4 in the official UFC middleweight rankings, and he is currently ranked the #5 Middleweight MMA fighter in the world by Fight Matrix.

Mousasi was born in Tehran, Iran to ethnic-Armenian parents during the Iran–Iraq War. His family name was changed in Iran long before his birth from Mofsesian to Mousasi. At the age of four, Mousasi and his family relocated to Leiden, Netherlands where he finished grade school before developing an interest in martial arts. Mousasi began training in judo at the age of eight and later boxing at age 15; a year later he became the amateur boxing champion of the Netherlands with a 12–1 record, earning nine knockouts. Mousasi then transitioned into kickboxing and then eventually to mixed martial arts.

Mousasi has relatives in both Iran and Armenia. He is an Armenian Apostolic Christian.

His older brother Gewik was a mixed martial artist before him, and Gegard decided to follow in his footsteps. Gewik is currently a prolific MMA trainer in Holland. He also currently handles the finances for Gegard's career payments.

Mousasi is the godfather of Satoshi Ishii's son Mousasi Ishi, who is named after him.

Mousasi's moniker, "Dream Catcher", was given by a friend which he was not fond of as he considered his style of fighting could not be named.