Systems and methods are disclosed for forming crowds of users based on wireless contexts of corresponding mobile devices of the users. In general, wireless contexts of mobile devices of a number of users are obtained. For each mobile device, the wireless context of the mobile device includes a wireless Personal Area Network (PAN) context of the mobile device, a wireless Local Area Network (LAN) context of the mobile device, or both. The wireless contexts of the mobile devices of the users are then utilized to form crowds of users. More specifically, in one embodiment, users of mobile devices having sufficiently similar wireless contexts are determined to be in the same crowd of users.