In general, aspects of the subject matter described in this specification can be embodied in methods that include the actions of receiving a search query initial input from a user, receiving a plurality of query auto-completions based on the search query initial input, receiving social graph data, the social graph data being specific to the user, for each query auto-completion of the plurality of query auto-completions, determining a ranking score, the ranking score being determined at least partially based on the social graph data, and transmitting instructions to display the plurality of query auto-completions to the user in a rank order that is determined based on ranking scores.