Denis Vieru (born 10 March 1996) is a Moldovan judoka who competes in the men’s half-lightweight 66 kg category. He competed in the men’s 66 kg event at the 2020 Summer Olympics in Tokyo, Japan.

He first rose to prominence after winning a gold medal at the European U-23 Judo Championships in 2016, the first Moldovan to do so since Marcel Trudov in 2005. Vieru won medals at a number of IJF Grand Prix and Grand Slam events
in 2019, including Moldova’s first Judo Grand Prix gold medal at the Antalya Grand Prix, another gold at the Baku Grand Slam, and defeated 2016 European champion Vazha Margvelashvili to win gold at the Grand Slam Paris.
He also defeated Ranto Katsura of Japan to win a gold medal at the 2019 Summer Universiade in Naples, where he was the flag bearer for the Moldovan delegation in the opening ceremony,
and won a bronze medal at the 2019 World Judo Championships. As of February 2020, he was ranked third in the world in the men’s half-lightweight category.

At the 2021 Judo Grand Slam Abu Dhabi held in Abu Dhabi, United Arab Emirates, he won the gold medal in his event. He won the gold medal in his event at the 2022 Judo Grand Prix Almada held in Almada, Portugal.