When new products and brands are introduced into other cultures, the speed and extent of the product's acceptance are important concerns for marketers. The spread of positive word of mouth (WOM) and the lack of negative WOM about the product or brand by early adopter groups are critical to the product's successful diffusion in a population. This is the first study to investigate the effects of consumers' cultural values on their WOM behavior. Data analysis from two samples indicates that the pattern, type, and target receivers of consumers' WOM activity depend on their cultural values. The authors use Hofstede's four cultural dimensions to test the effects of cultural values on WOM behavior to social in- and out-groups. They find that all four dimensions have significant effects on WOM engagement to those groups. Although the authors could not determine the causal nature of the relationships because of the sample design used, they argue that marketers should monitor the cultural values of their market to anticipate in- and out-group discussions and the choice of appropriate brand communication strategies in other countries.