This case study investigates fashion brands that have entered the pet fashion market. A total of 25 cases were identified and analyzed from three perspectives: 1) product types, size systems, prices, 2) design aspects, fabrics, patterns, styles, and 3) marketing strategies. The study results are as follows. First, the product types of pet fashion are not diverse, and only the sizes of small dogs can be found. However, there is a significant price difference between brands. Second, knitted fabrics with good elasticity are mainly used for pet fashion products, and patterns incorporating their brands are extremely common. The style is casual and sporty. Third, marketing strategies should include a new line within a brand or launch a single specialized brand as a one-shot test for consumer reaction. Additionally, it has been expanded and presented as a family look to meet the needs of the petfam. Further, existing fashion brands and retail-based brands select diverse small-scale dog fashion product brands and expand their operation as a dog lifestyle total selectional shop. Therefore, brands entering the future should consider strategies such as size segmentation, product diversification, and premium price of high-quality materials that help market products such as the expansion or promotion of existing brands.