This study takes a perceived affordance approach to explain how differences in teenagers’ mobile messaging behavior associate with indicators of friendship maintenance behavior. Based on a survey among 1943 teenagers, a structural equation model was tested in which their appreciation of three main affordances of mobile messaging predicted the companionship and support that they derive from their friends through their instrumental and expressive mobile messaging behavior. The model fitted the data well: teenagers’ appreciation for anytime–anyplace connectivity, private communication, and control over message content explained to what extent they use mobile messaging to micro-coordinate, to chitchat with friends, and to intimately self-disclose, thereby indirectly explaining the companionship and support that teens derive from friends. This finding supports the notion that inherent characteristics of technology play a role in contemporary relationship management by driving social uses of the technology.