Crowdfunding enables project initiators to obtain money from unknown supporters worldwide to finance their business ideas. To receive funding, an adequate and effective communication between project initiators and supporters is very important. However, traditional marketing activities’ high costs are often unaffordable. Therefore, guerrilla marketing represents an unconventional and inexpensive way to gain reach and popularity, especially if done via social media. Research has largely neglected the ways different marketing activities and social media influence crowdfunding success. The contribution of our paper is that we provide a theoretical and integrative understanding of how guerrilla marketing has an influence on crowdfunding success via social media. We derive a preliminary model on crowdfunding success from literature and test it against seven cases of crowdfunding campaigns which employed guerrilla marketing in their social media campaigns. Subsequently, using inductive case analysis, we extend the current understanding of crowdfunding success to an initial research model.