This thesis aims to investigate the cola market situation in Thailand and the possibility of a local brand to compete with global brands. Due to the high value of this market, every cola company wants to get the biggest piece of the market share pie. Moreover, there is a situation regarding a global cola brand Pepsi falling into the trouble in terms of logistics and distribution channels after having been separated from its local partner company. In addition, Pepsi’s ex-partner company has launched a new cola brand into the market, a completely separate operation without any ties to Pepsi. As a result, the cola market in Thailand now has witnessed fierce competition and it attracts many players in the beverage industry to take part. Therefore, this research is designed to understand the brand preference, brand substitution, brand loyalty, taste preference, and relation between several factors from customers’ perspective to answer the possibility of a local brand competing with global brands, as well as to investigate the general cola market situation.   Information was collected by questionnaire which was answered by 420 participants, 51 percent of which were female and 49 percent were male. The results of the questionnaire found that their brand preference is actually in an opposite direction with the current cola market share, due to the effect of cola brand substitution in the market. Moreover, the research found that taste preference and gender have an influence on brand preference, while frequency of drinking and other demographics do not have any effect on brand preference