List of highest ranked tennis players per country

This article lists the professional tennis players who reached the highest ranking among their compatriots during the Open Era. The rankings used are ATP Rankings for men (since 23 August 1973 for singles, and 1 March 1976 for doubles) and WTA Rankings for women (since 3 November 1975 for singles, and 4 September 1984 for doubles).
On 11 September 2017, Garbiñe Muguruza and Rafael Nadal made Spain the first country since the United States 14 years ago to simultaneously top both the ATP and the WTA rankings, with Muguruza making her debut in the No. 1 spot. The most recent previous such pair were Serena Williams and Andre Agassi, 28 April to 11 May, 2003.