Slogans have extensively been used as an important element in advertising campaigns. The phrase emphasized in a slogan is expected to be remembered by the audience and/or consumers of particular products or company (Brierley 2002). Advertising slogan can have a potential wordof-mouth effect from the frequent use in daily social contexts that may not be related to any product purchase or use occasion (Mitchell et al. 2007). The role of slogan is so crucial that the announcement of changes in advertising slogan significantly affects market-value (Mathur and Mathur 1995). Thus, the purpose of this study is to investigate the effect of vagueness in advertising slogans on consumer’s attitude. The study attempts to answer few research questions as how extensive is vagueness in advertising slogans? In what kind of patterns may it exist? How would the use of vagueness in advertising slogans influence viewers/consumer’s attitude and behavioral intention? What are the factors that may mediate and moderate such influence? The result of the study is expected to bring a new understanding about the vagueness embedded in advertising slogans and to shed a light on one of sub-elements in abstractness (vs vividness) concept.