Brand positioning increasingly uses comparative advertising (Beard, 2018). This research contributes to the comparative advertising literature by focusing on the impact of vividness of the ad on Indirect Comparative Advertising (ICA). Vividness has been shown to be important in advertising effectiveness, and this research extends this to include ICA and potential moderating variables. We employ a between-subjects experimental design (n = 288 respondents from USA). Vividness is manipulated and, as respondent inherent conditions, we include measures of need for cognition, cognitive resource allocation, product and category involvement. We find that vividness positively impacts most responses to ICA ads except attitude certainty and processing modes. Cognitive resource allocation, involvement and familiarity affected responses to ICA. Need for cognition did not. The only interacting moderator variables were need for cognition and familiarity with higher attitude certainty. Advertisers should pay attention to vividness of information in an ICA ad as it can influence consumer response.