The most important asset needed to achieve the competitive advantage is having a strong brand equity. In this study, the relations between the dimensions of consumerbased brand equity and those of word of mouth marketing were analysed. In addition, the mediating role of the brand preference was checked. The sample consisted of 1000 people living in Istanbul, Ankara, and Izmir. The sampling method used was quota sampling. In the conclusions of this study, it was observed that: there are effects of brand awareness and brand association dimensions on the negative word of mouth marketing, perceived quality on the positive and negative word of mouth marketing, and brand loyalty on the positive word of mouth marketing. Brand preference has a partial mediation role in the relations between the perceived quality dimension of consumerbased brand equity and the dimensions of positive and negative word of mouth marketing.