Mobile payment is becoming an evitable trend in the globe and is well expanding rapidly into emerging countries. Many research models are developed and confirmed that behavior intention is an important fact which decides the level of using mobile payment among users. The existing research models have made empirical evidences confirming behavior intention de-pended on performance and effort expectancy. This research expands previous empirical evidence by involving perceived transaction speed as an important explanatory variable to both performance expectancy and effort expectancy and also captures how behavior intention is influenced by performance expectancy and effort expectancy among Cambodian users. A total of 200 questionnaires were collected, analyzed and summarized for this study. Result reveals that performance expectancy and effort expectancy affect positively and significantly on behavior intention. Perceived transaction speed has a positive and significant relationship with effort expectancy but Perceived transaction does not have any positive and significant relationship with performance expectancy. Result from this study also concludes the role of perceived transaction speed which is affecting intention to use mobile payment among users. However, there are some limitations to be addressed for the future researches; this research may include larger samples to find out the clear effect on behavior intention of the end-users.