This study aimed to analyze the influence the word of mouth, service quality and advertisement to decision of online purchasing of fashion product. Subjects in this study were FEB students Muhammadiyah University of Yogyakarta have ever made a purchase online. In this study sample of 100 respondents were selected using purposive sampling method. The analysis tool used is the Statistical Package For Social Sciences (SPSS) Based on the analysis that has been done shows that the word of mouth of positive and significant impact on purchasing decisions, service quality of positive and significant impact on purchasing decisions, advertisement of not significant and negative impact on purchasing decisions