Methods, systems, and apparatus, including computer programs encoded on a computer storage medium, for providing knowledge panels. In one aspect, a method includes determining an entity that is referenced by a received search query. Content items relevant to the entity are identified. A set of knowledge modules is selected for presentation in a knowledge panel for the entity. The knowledge panel can be a portion of a search results page in which knowledge modules are presented. Data that causes the knowledge modules to be presented in the knowledge panel is provided to a user device.