Marjolein Buis (born 11 January 1988) is a Dutch retired wheelchair tennis player.

In 2016 Buis won her only grand slam singles title at the French Open.

It turned out that she has a connective tissue disorder, the Ehlers–Danlos syndrome, which affects the stability of the joints.

She qualified for the Paralympic Games in London 2012 and reached the quarterfinal in singles and won gold in doubles with her partner Esther Vergeer.

At the Paralympic Games in Rio 2016 Buis reached the quarterfinal in singles again and this time won silver in doubles with her partner Diede de Groot.