Dušan Lajović (Serbian Cyrillic: Душан Лајовић; born 30 June 1990) is a Serbian professional tennis player.
Lajović has won one doubles title on the ATP Tour in his career. On 29 April 2019, Lajović reached his best singles ranking of world No. 23. On 8 June 2015, he peaked at No. 104 in the doubles rankings. He is best known for his clay court craft and strong flowing groundstrokes, especially his one-handed backhand. In recent years, he has proven to be a reliable and consistent player for the Serbian Davis Cup team contributing to their achieving one final, one semifinal, and three quarterfinals. His best individual result has been a Masters 1000 final.
For a long time, Lajović primarily played on the Futures circuit and the Challenger circuit. In 2011 he qualified for the Kremlin Cup, and lost in the first round of the main draw. In the 2011 St. Petersburg Open, he reached the quarterfinals for the first time in his career. In 2012, he began working with a new coach, Boris Bošnjaković, played in the Davis Cup for the first time, reached the finals of 2012 Orbetello Challenger and won the 2012 Samarkand Challenger. Replacing an injured Janko Tipsarevic, he played two live rubbers in the 2013 Davis Cup final, including the deciding rubber against Radek Stepanek of the Czech Republic. He was defeated comfortably in both but was praised by team-mate Novak Djokovic for how he coped with the big occasion.