Understanding and managing consumer's complaint behavior (CCB) is incredibly essential in the competitive business environment. This paper aims to investigate whether male and female millennial consumers differed in their complaint behavior and its aftermath. The study examines the moderation effect of gender on millennial's complaint behavior. The researchers distributed a total of 430 questionnaires to millennial consumers who have experienced a dissatisfaction episode within 12 months. The results show that gender was significantly associated with millennial's complaint behavior. These findings are generic across sex-type. This paper discusses the theoretical and managerial implications of the findings.