PurposeThe practice whereby a non-official sponsor brand attempts to “ambush” an official sponsor’s rights continues to threaten sporting events. A key motivator of the ensuing regulatory response is grounded in the ambiguity that ambush marketing generates, namely, by obscuring public awareness of the legitimate sponsor. However, the cognitive processes underpinning sponsorship identification have only recently been investigated empirically. The purpose of this paper is to investigate the effects of ambush advertising on sponsorship memory.Design/methodology/approachA 2 (brand advertising: sponsorship-linked vs non-sponsorship-linked) × 2 (ambush advertisement: ambush advertisement vs filler) experimental design was used to test the impact of exposure on sponsor recall and recognition.FindingsThe results indicate that exposure to ambush advertising has adverse effects cognitively. When presented with a sponsorship-linked advertisement and an ambush advertisement, the participants had diminished recall of who the legitimate sponsor was, and were less likely to recognize them.Research limitations/implicationsThis work has important theoretical implications in that it draws together the existing literature on sponsorship, advertising and cognitive fields. Moreover, on a practical level, this work informs the debate on increased regulatory intervention into ambushing practices, which is centered on tensions between balancing fair marketing practice with the rights of sponsors and event organizers.Originality/valueTo date, there is a paucity of research that examines the effects of ambushing in a sports sponsorship context. The unique contribution of this study is that it shows the process through which ambushing advertising adversely impacts sponsors’ rights.