EXHIBIT 8.1

List of Significant Subsidiaries of Qihoo 360 Technology Co. Ltd. (the “Registrant”)

As of December 31, 2015

Subsidiaries

1. Qizhi Software (Beijing) Co., Ltd., a PRC company

2. Tianjin Qisi Technology Co., Ltd., a PRC company

3. Qifei Xiangyi (Beijing) Software Co., Ltd., a PRC company

4 Mobi Magic (Beijing) Information Technology Co., Ltd., a PRC company

5 Qiji International Development Limited, a HK company

6. 360 International Development Co. Limited, a HK company

7. Qifei International Development Co. Limited, a HK company

8. Tech Time Development Limited, a British Virgin Islands company

Variable Interest Entities

1. Beijing Qihu Technology Co., Ltd., a PRC company

2. Beijing Star World Technology Co., Ltd., a PRC company