The purpose of this study was to investigate brand slognas that are effective in explaining how brand identity affects consumers. The effect of congruity between brand slogan and self-image (low and high) on attitude to slogans and brands were anaylzed. The moderating effect of self-monitoring (low and high) was also investigated. Survey data from 177 people in their 20s-30s were analyzed through descriptive statistics, exploratory factor analysis, and two-way ANOVA. First, congruity between slogan and self-image had a positive effect on both slogan and brand attitude. In other words, the higher the congruity between slogan and self-image, the more positive the attitude toward the slogan and brand. Second, no interactive effect was found in congruity between slogan and self-image and self-monitoring on slogan attitude; however it was identified for brand attitude. Again, in a group with high congruity between slogan and self-image, attitude toward the brand was more positive when self-monitoring was higher than when it was low. In conclusion, brand slogans that can represent the self-image of highly self-monitoring consumers are effective. In particular, this is meaningful as it has revealed its relationship with the impact of identity self-image congruity and self-monitoring on brand attitudes in fashion brands. These results offer meaningful guidance in determining brand slogans according to consumers’ personal characteristics.