Consumers worldwide are daily exposed to very similar advertisements, which is the reason guerrilla marketing emerged. It is popular in Western countries, where numerous successful examples can be found. Unfortunately, it hasn't developed to the same extent in Croatia. The aim of study is to theoretically and practically analyze the impact of guerrilla marketing on consumer behavior and to determine the difference in its acceptance among consumers of Generations Y and Z. The first part pertains to an introduction to the problem of the research. The second part defines the process of purchasing decisions and its influencing factors. The third part theoretically addresses guerrilla marketing. The fourth part focuses on the behavior patterns of the mentioned generations. The fifth part examines the impact of guerrilla marketing on the consumer behavior of these generations, using a sample of 5 participants in each focus group. The results of the empirical study demonstrate that guerrilla marketing has a positive effect on the majority of participants in the sample, with Generation Z showing more positive reactions compared to Generation Y. Members of both focus groups believe that guerrilla marketing has significant potential in Croatia, which leaves room for considering the implementation of this marketing approach into the marketing strategies of Croatian companies.