Niklaus Fleury (born 10 May 1945) is a Dutch former professional tennis player.

[1] he played his first tournament at the Netherlands National Championships in 1965 where he reached the quarter finals, but lost to Jan Hajer.

[1] In 1967 he won his first singles title at the Tilburg International Indoor tournament against Jan Hajer.

[1] In 1969 Fleury won his second and final title at the Netherlands National Championships against Evert Schneider,[1] and made his Davis Cup debut that year, going on to feature in six ties for his country.

In 1967 he featured in the mixed doubles main draw at Wimbledon.