This big opportunity is seen by the retail store that brings them to create a new kind of fashion, named fast fashion. This paper examines that there is a significant relationship between the motivation of buying fast fashion and the frequency of purchasing fast fashion in Thai teenagers. The result show a relationship at p < 0.05 level (x = 16.995a, df = 9, p = 0.049). The results show a significant number at the level of significant. A mix-methodology approach is used to gather quantitative and qualitative data to observe Thai consumer’s behavior towards fast fashion. The populations for this study comprise residents of Bangkok in 2016 of ages 18-35 years, with 100 subjects partaking in a questionnaire, and 10 subjects partaking in in-depth interviews. Results show that the motivation of buying fast fashion is significantly pushing Thai Teenagers to buy fast fashion more than once in the month.

Based on data obtained from Market Line, a business information company, the global apparel industry has been growing at a 4.78% yearly rate since 2011. Now valued at nearly $1.4 trillion dollars in sales for 2017, the industry shows no signs of slowing as the market is projected to experience 5.91% yearly growth over the next three years. By 2020, the market size of the apparel industry is expected to reach a mind-boggling $1.65 trillion sales in US dollars worldwide.

According to Barnes, L., and Lea-Greenwood, G. (2006, p259) fast fashion is a business strategy which aims to processes involved in the buying cycle and lead times for getting new fashion product into stores, in order to satisfy consumer demand at its peak. Teenagers just love fashion trendy and up to date. The tendency of teenagers who like this kind of fashion gives the opportunity for retail businesses in creating a new type of fashion called fast fashion. There are several things that differentiate fast fashion with fashion in general. The differentiating factor that can be seen from the speed of a fashion company view the trend, produce, distribute and change the fashion in store rapidly.

Much fast fashion retail store is regularly issued new models in the store. Then the companies distribute clothes to the supply chain strategy that quickly and accurately to reach the store. Furthermore, within a week if the clothes are not sold, the retail store will withdraw and replace them with new ones. The purpose of the fast fashion’s retail store strategy is to establish customer mindset for always coming to the store and shop. The attitude of loyal customers will always push the fast fashion business to evolve over time. Consumer purchase behavior can be defined as behavior that is demonstrated by consumers when looking for, assessing, purchasing, using and abandoning products and services for which it is expected that they will satisfy the consumer‘s wishes and needs in the process of change (Solomon et al., 2010).

The author perceives the increasing of the teenagers’ demand in fast fashion as one of an interesting topic to be observed. The purpose of this research is to find the relationship between the motivation of buying fast fashion and the frequency of purchasing fast fashion in Thai teenagers. The author considers it is important to do research in order to understand Thai teenager’s purchasing behavior in the dynamic world of clothing trends.