The Internet is changing the transaction pattern of B2B markets. One of the major concerns of IT knowledge-based companies is how to take advantage of B2B online markets. These companies believe that the only possible strategy for entering these markets is to launch independent websites, and they are usually reluctant to enter these markets due to the requirements such as financial resources and skilled human resources. The literature showed that there were different strategies for entering these markets. This study aimed to identify the factors influencing the selection of B2B online market entry strategies in IT knowledge-based companies but given the complexity of choosing the right strategy, it is a complex and unstructured issue, with various stakeholders, both internal and external, involved. Therefore, due to this complexity and the strong role of the human factor in it, the methodology of soft systems methodology has been used. The results showed that the factors contributing to the selection of B2B online market entry strategies in IT knowledge-based companies included entry time, external beneficiaries' characteristics and needs, corporate resources, corporate control strategy, corporate IT capabilities, external beneficiaries' IT knowledge and motivation, and product.