Samuel "Sam" Groth (born 19 October 1987) is an Australian professional tennis player. His highest ATP singles ranking is World No. 53, which he reached in August 2015. His career high in doubles was World No. 24, also reached in February 2015. Groth's best singles result to date is a semi-final appearance at the 2014 Hall of Fame Tennis Championships. He is best known for hitting the fastest serve on record at 263 km/h (163.4 mph) in 2012 at the ATP Challenger in Busan.