Sisi (stylized as SiSi; originally si si) is the brand name of a wide range of fruit-flavoured beverages produced by Dutch beverage manufacturing company Vrumona under a joint venture with Heineken International since 1951.

Between 1951 and 1969 there were a number of similarly named drinks, including Cas-Si (blackcurrant), Ceri-Se (cherry) and Grapy (grapefruit).

In 1957, cabaret singer Wim Sonneveld on Radio Luxembourg sung the company's first jingle "ome Daan the Si-Si-liaan".

In 1972, and 1973, two well known Dutch actors, John Kraaijkamp sr. and Rijk de Gooijer, acted in some television commercials for the brand.

Sisi has touted itself as having half as much sugar as similar products produced by its competitors.