Given that numerous fashion brands constantly struggle to survive, it is important to learn how consumers evaluate and change their attitudes toward the downward extensions of mass-production fashion businesses, particularly those that originate in Hong Kong. Through capitalizing on the parent brand’s equity earned through enhancing consumer preferences and building loyalty, companies’ brand extension strategies can lead to better profits and sales for fashion brands. Based on the categorization theory and the theory of perceived fit, this study examines how consumers’ familiarity, trust, perceptions of quality, and perceptions of the brand name of the parent brands influence them when evaluating a business’s downward extension. This study also investigates how the effect of the consistency, similarities in product features, and pricing of the extension’s brand concept influences consumers’ purchase intentions toward produces from the downward extension. To achieve the objectives of this study, snowball sampling was used to gather a total of 203 data sets for analysis through methods such as t-tests and stepwise regressions. The results indicated that familiarity with and trust in parent brands, along with the perceived quality of the parent brands’ products, were positive influences on consumers’ evaluations of downward extensions. The extensions’ consistency with the brand concept, product substitutability, product transferability, and pricing positively influenced higher purchase intentions. Consequently, this study highlights that perceptions of the quality of the parent brands contributes most strongly to positive evaluations, and the extension’s pricing contributes most significantly to purchase intentions.