The majority of studies of the effectiveness of comparative advertising (CA) have been primarily focused on America and Asia than on European countries. The transferability of comparative advertising practices across markets is still largely unexplored notwithstanding that the effects of CA may vary according to the degree of novelty of comparative advertisements in the country (Nye et al. 2008). This observation is particularly interesting in Europe where countries such as the United Kingdom and Sweden have used CA for a longer period than France (Diannoux and Herrmann 2000). This study examines for the first time the role of opportunity, ability, and motivation to process the message on perceived manipulative intent and consumer evaluations of advertising by proposing a model of effectiveness of direct and indirect comparative advertising. Analyses of responses from participants in France, the United Kingdom, and the United States indicate that direct comparative attacks are not equally embraced by consumers across countries. Furthermore, they tend to generate greater suspicion regarding the manipulative intent than indirect formats. The study provides for the first time evidence that perceived manipulative intent varies according to CA format and evidence of moderating effects in the relationship between motivation to process the message and perceived manipulative intent of Direct Comparative Advertising (DCA). The motivation to process the message reduces perceived manipulative intent only in countries with low familiarity with DCA. The ability to process the message moderates the relationship between processing motivation and perceived manipulative intent.