Jacques Grandjean (born 1 February 1954) is a Belgian former professional tennis player.

[1] Grandjean was a Davis Cup representative for Belgium and debuted in a 1982 tie against Israel in Eupen, losing his singles rubber in five sets to Shahar Perkiss.

In 1983 he featured in further ties against Poland and West Germany.

16) at the 1983 Brussels Indoor, one of his two Grand Prix circuit main draw appearances.

[2] He won a national championship in doubles in 1985.