Ruben Bemelmans (Dutch pronunciation: [rybən beːməlmɑns], born 14 January 1988 in Genk) is a Belgian male professional tennis player. His career-high ATP rankings are World No. 98 in singles, achieved in April 2015, and World No. 128 in doubles, achieved in October 2012. As a qualifier, Bemelmans reached the quarterfinals of Vienna in 2013, defeating No. 4 seed Philipp Kohlschreiber en route.
Bemelmans competes mainly in the Challenger tour circuit. He won his first Futures event in Espelkamp, Germany in July 2007, and has a total of nine titles at this level. His best performance to date was in winning the Volkswagen Challenger event in Wolfsburg in March 2009, winning three matches in qualifying before going on to beat Stefano Galvani of Italy in the final. He won again this tournament in 2011.
In February 2010 Bemelmans succeeded in qualifying for his first ATP level event, the Zagreb Indoors tournament. However he lost in the First Round to Alexandre Sidorenko of France 6–7, 6–3, 3–6.
In September 2010, Ruben played for Belgium in the Davis cup play-off tie against Australia. He was a late replacement for an injured Steve Darcis. He played Lleyton Hewitt with nothing to lose; but after a solid effort, he succumbed in a 6–7, 5–7, 6–2, 4–6 duel.