In this study, a three-step methodology is proposed. To begin with, a total of seven main criteria and 23 subcriteria that affect the selection of online shopping websites are determined by searching the literature and interviewing people. Next, a questionnaire is applied to the people from Turkey and Croatia. It is evaluated using AHP methodology to find the main and sub-criteria weights from the perspective of Turkish and Croatian people. Furthermore, a second questionnaire for ranking three popular online shopping websites in Turkey has been applied. Finally, online shopping websites are ranked as B, A, and C based on the scores obtained from the second questionnaire and criteria weights found in the second step. After estimating the decision weights of the sample from Croatia, we use that as a "what if" analysis for websites A, B, and C. Customers' shopping behaviors from those online shopping websites are analyzed using SPSS.