Online shopping has generally become ubiquitous; however, the concept is still emerging in some developing countries. This cross-cultural study comparatively explores the effects that national culture has on the behaviors of shoppers in Mongolia's emerging online shopping markets and Taiwan's developed online shopping markets. This study specifically investigates the factors leading to online shopping acceptance and identifies three external formative antecedents: website design, customer service and shipping. The PLS-SEM results reveal that the Taiwanese and Mongolian samples differ from each other regarding their support for our proposed model. The significant difference lies in the antecedents of perceived ease of use: website design does not exert an effect in Taiwan, whereas customer service does not exert an effect in Mongolia. The managerial implication would also be discussed.