Methods, systems, and apparatus, including computer program products, for generating query refinements. In one implementation, a method includes dividing a search query into one or more n-grams; determining that each of the one or more n-grams represents a same concept, and in response to the determination: selecting one or more candidate refinement queries; determining one or more categories for the search query; determining one or more categories for each of the candidate refinement queries; determining a respective first score for each of the candidate refinement queries; and identifying as query refinements for the search query one or more of the candidate refinement queries based on the first scores.