This research aims to compare the influence of service quality on intention to use broadband internet through attitudes and technology acceptance, as mediator variables between large and small broadband internet service providers (ISPs) in Thailand. A comprehensive review of the literature has modified the development of this behavioral model that explains intention to use of broadband internet. A data set from two groups: large and small broadband ISPs, nationwide survey was conducted in Thailand (n = 928 consumers). The theoretical model was tested using structural equation modeling. The findings show that integrated models have good explanatory power (78.3 percent) to predict customer’s intention to use broadband internet. The results of this study are as follows. Firstly, service quality: tangible, reliability, responsiveness, assurance and empathy, supports second-order factor analysis. Service quality has an influence on attitude, perceived usefulness, perceived ease of use, and intention to use broadband internet both two types of service providers. Secondly, perceived usefulness has a significant effect on attitude, and intention to use only in small companies. Thirdly, attitude, perceived usefulness, and perceived ease of use as mediator variables have a positive effect between service quality and intention to use broadband internet. This study proposes customer acceptance on broadband internet using a modified TAM.to reveal the impact of service quality on intention to use. The results of this study can be replicated and extended to ASEAN countries. The conclusions and implications for management provide alternatives for companies to increase the number of internet users in order to improve overall quality of life.