Understanding customers’ behavioral intention has always been a critical issue in the B2B Online Travel Portal business in the tourism industry. Every B2B Online Travel Portal aims to be the leader in the market. As the online booking in the tourism industry is competitive, B2B Online Travel Portal needs to understand their customer’s perception to better serve their needs. Therefore, the purpose of this study is to identify the relation between Various Factors of Online Portal and Travel Agencies’ Purchase Decision on B2B Online Travel Portals in Thailand and to find the most significant factor that affects travel agencies purchase decision. In this research, the independent variables are website design quality, information quality, system quality, customer satisfaction, customer trust, word of mouth (WOM), price perception, ease of use, the service quality. Purchase decision represents the dependent variable. There are nine hypotheses in this study. The collection period was within three weeks period between 26 June-13July 2018. A total of 270 respondents were chosen as the accurate target population, consisting of travel agencies’ reservations staffs, travel agencies’ manager and travel agencies’ management who had an experience using B2B Travel Portals in Thailand, based on two screening questions. The statistical program analyzed all of the data. Pearson Correlation Coefficient Test was utilized to test the relationship between each variable. Based on research findings regarding hypotheses testing, the entire null hypotheses (Ho) were rejected. All alternative hypotheses have significant relationship with Purchase Decision. The highest factors affecting relationship is customer satisfaction with(Correlation Value= 0.588), followed by consumer trust (0.572), service quality (0.528), word of mouth (0.515), ease of use (0.507), price perception (0.505), system quality (0.443), information quality (0.402) and lastly website design quality (0.368) has less relationship with Purchase Decision. From the findings of this research, the researcher hopes that the results will useful for B2B Online Travel Portal companies.

Keywords: Website Design Quality, Information Quality, Word of Mouth (WOM), Price Perception.