This paper examines the impact of product category risk and consumer knowledge on brand extensions. In addition, the impact of similarity and brand reputation is replicated in a new (Scandinavian) setting. In a quasi-experimental study including three hypothetical brand extensions, it was found that evaluations of brand extensions co-vary positively with perceived similarity to, and reputation of, the parent brand. The reported findings also indicate that a firm may benefit from its recognised brand when the perceived risk in the product category extended into is high.