The purpose of this present research was aimed to find out the factors that affect Indonesian consumers on making a decision to purchase smartphones online. The variables tested on this study were included perceived trust, perceived risk, perceived usefulness and perceived website quality toward online buying decision for smartphone in Indonesia. The process of data collection was done by using a questionnaire as the instrument of the survey. The researcher succeeded in collecting 330 of Indonesians who had experience of purchasing the smartphones via online channels. From the total of respondents who participated in this research, female respondents took a big portion of 66.1% or equivalent to 218 people aged from 18 - 30 years old of 46.4%. Most of respondents have completed a bachelor's degree (42.4%), worked as employees (47.6%) and earned a monthly income below Rp. 3,000,000 (37%). Based on the period of online shopping use, 31.8 % of respondents have been using online shopping for 1-2 years. In addition, 153 respondents of this study stated not sure whether they do online shopping or not per month. According to the findings of the study, it revealed that perceived usefulness was the most influential factor on Indonesian consumer’s online buying decision for smartphone, followed by perceived website quality and perceived trust. On the contrary, the perception of risk affected Indonesian consumers negatively on the deciding to purchase smartphones online.