The star sued Topshop's parent company, Arcadia Group Brands Ltd, for $5.5.million (€3.7m) for selling t shirts through 2011 and 2012 which featured an image of the singer that was taken during her We Found Love video shoot.
Rihanna claimed that the high street giant had wrongly confused customers with "an emotional connection to their heroine" into thinking the image was endorsed merchandise.
However, Topshop says they had the right to use the image as they had bought the licence to use it from the photographer who took the photograph.
The brand also maintains that Rihanna is not legally entitled to a "free standing image right" over the use of her picture in the UK.
High Court judge, Mr Justice Birss, who took just two minutes to make his judgement in favour of Rihanna, said: "The mere sale by a trader of a t-shirt bearing an image of a famous person is not, without more, an act of passing off."
He continued: "However, I find that Topshop's sale of this T-shirt was an act of passing off."