This study focuses on the influence of colour on the online purchasing intention of consumers. The literature review about colour associations showed that several factors could play a mediating role in the relationship between colour and purchasing intention. Two of these factors are emotion and trust, which have been shown in previous studies to have a relationship both with certain colours and with online purchasing intention. The aim of the study was to investigate the relationship between colour and online purchasing intention, taking into account the influence of emotion, trust and cultural differences between Western and Asian cultures. The method used to investigate these relationships was an online survey, which has been conducted amongst 522 participants from seven countries that can be separated in Western (The Netherlands, Germany and United Kingdom) and Asian (China, Singapore, Malaysia and Indonesia) cultures. The survey asked the participants about their cultural background, attitudes towards the product and message, emotions, level of trust, colour influences and experience. When filling in the survey, an image was presented to the participants that showed an online shopping background, a coloured context and a simple digital photo camera. Only the coloured context of this image varied amongst the participants; every participant answered the questions being exposed to one colour: red, yellow or blue. The results of the study showed that the direct relationship between colour and online purchasing intention was supported only for the colour yellow and that emotion indeed played a mediating role between colour and online purchasing intention, although no clear relationships could be defined between colours on the one hand and emotion and trust on the other hand. Concerning the cultural differences, results on emotion were found for both Western and Asian cultures, but trust was shown to influence the relationship between colour and online purchasing intention only for Asian consumers. The results partly confirmed the findings of previous studies, but also highlighted areas that need to be studied in more detail or by using another method. Overall, the study showed that colour does influence online purchasing intention, so companies should consider this when persuading consumers to buy their products.