John Alexander, Australian tennis player and politician
John Gilbert Alexander (born 4 July 1951) is an Australian politician and former professional tennis player.

As a tennis player, Alexander reached a career-high singles rank of No. 8 in the world in 1975. He reached the semi-finals of the Australian Open singles on three occasions, and won the doubles in 1975 and 1982. He also played in the Australian team that won the 1977 Davis Cup. After the end of his playing career, Alexander worked as a tennis commentator and managed various sports-related businesses.

Alexander won the Division of Bennelong for the Liberal Party at the 2010 election, and retained the seat in 2013 and 2016. He resigned effective 11 November 2017 due to constitutional ineligibility arising from his dual citizenship of the United Kingdom. He renounced his UK citizenship and stood as the Liberal Party candidate at the by-election, held on 16 December 2017, which he won. In November 2021, Alexander announced his retirement from politics.