Alexandr Dolgopolov (born 7 November 1988), formerly known as Oleksandr Dolgopolov Jr. (Ukrainian: Олександр Олександрович Долгополов, romanized: Oleksandr Oleksandrovych Dolhopolov), is a Ukrainian retired professional tennis player. He changed his forename spelling to the current form in May 2010. Dolgopolov reached the quarterfinals of the 2011 Australian Open and achieved a career-high singles ranking of World No. 13 in January 2012.

Alexandr's father, Oleksandr Sr., was a professional tennis player for the Soviet team, and his mother was a gymnast. He started playing tennis at age 3, coached by his father. The senior Dolgopolov was also the coach of Andrei Medvedev, Ukraine's most successful tennis player to date. At a young age, Dolgopolov lived on the tour with his parents, traveling frequently and playing players such as Medvedev, Andre Agassi, and Boris Becker. Players such as Jim Courier remembered hitting balls with Dolgopolov when he was a toddler.

As a junior, Dolgopolov reached as high as No. 21 in the combined world rankings in January 2005. His best showing at a junior major was a quarterfinal at the 2005 French Open Boys' Singles, where he lost against Christian Bak.

Dolgopolov made his ATP Tour debut in September 2006 at the BCR Open Romania as a qualifier, losing in the first round to Christophe Rochus. He was also part of the Ukrainian Davis Cup team in the tie against Great Britain, where he was defeated by Andy Murray.

Eventually, the younger Dolgopolov decided that he wanted less of his father's influence and develop himself in his own way. In 2009, at age 20, he parted ways with his father and enlisted the help of Australian Jack Reader as his coach. He also changed his name from Oleksandr Dolgopolov Jr. to Alexandr Dolgopolov. Dolgopolov and his father didn't speak for six months but have since reconciled with Dolgopolov Sr. stating that he is very proud of his son.

Dolgopolov started the year at the 2010 Brisbane International, where he qualified for the tournament by beating Joseph Sirianni and Kaden Hensel. In the main draw, he defeated Bernard Tomic, before losing in the second round to Radek Štěpánek in three sets. At the 2010 Australian Open, he lost in the first round of qualifying to Simon Stadler in three sets.

Dolgopolov qualified for the 2010 Monte-Carlo Rolex Masters with wins over Santiago Ventura and Mischa Zverev, but lost to Julien Benneteau in the first round. Dolgopolov continued to the 2010 Mutua Madrileña Madrid Open, where he qualified to get into the tournament. In the first round, he beat Andreas Seppi, but in the second round lost to eventual champion Rafael Nadal in straight sets.

At the 2010 French Open, he beat Arnaud Clément in a long five-setter. Dolgopolov upset 12th seed Fernando González in straight sets. This was the biggest win in his career and best showing at a Grand Slam up to that point. In the third round, he lost to Nicolás Almagro.