Grigor Dimitrov (Bulgarian: Григор Димитров, pronounced [ɡriˈɡɔr dimiˈtrɔf]; born 16 May 1991) is a Bulgarian professional tennis player. His career-high ATP singles ranking is world No. 3, which he achieved in November 2017 after winning the 2017 ATP Finals.

Dimitrov is the most successful Bulgarian male tennis player to date, both in terms of ranking reached " as of 2017 he is the only Bulgarian tennis player ever to be ranked inside the top 10 ATP Singles " and prize money won, being the only male Bulgarian player to reach US$1m and later $15m.

Dimitrov is also the first (and only) Bulgarian male tennis player to win an ATP title in singles (after he won in October 2013 at Stockholm) and reach a final in doubles (in 2011) as well as the only Bulgarian male player to reach the third round or better at a Grand Slam tournament. Dimitrov is also the first Bulgarian to qualify for, and later win, the ATP Finals. He has won 8 ATP singles titles to date.

Prior to his professional career, Dimitrov enjoyed a successful junior career, in which he held the world No. 1 ranking and won consecutive grand slam boys' singles titles at the 2008 Wimbledon Championships and the 2008 US Open, at the former he defeated future men's doubles No. 1 player Henri Kontinen in the final.