Smartphone apps allow retailers to track the location of their customers and provide the opportunity to reach them with location-based mobile ads. However, the efficacy of these ads often suffers from consumers’ feelings of intrusiveness. Little research has investigated how location-based mobile messages should be designed to maximize their effectiveness and avoid undesired outcomes such as feelings of intrusiveness. The present study tested the effect of openness in ad design, in interaction with location congruency of mobile advertising, using a virtual reality supermarket setting. A process of moderated serial mediation demonstrates indirect positive effects of ad openness on brand choice (via intrusiveness and Aad), moderated by location congruency. Specifically, openness in mobile ad design lowers perceived ad intrusiveness, which positively affects consumers’ brand choice (via Aad). This effect is stronger for ads that are presented in a location-congruent situation than for location-incongruent ads.