When a social networking system receives a request from a requesting user for a content item associated with one or more comments, the social networking system determines an interest score for each comment. The interest score for a comment indicates a measure of the user's likelihood of being interested in the comment. Based on the calculated interest scores, the social networking system selects one or more comments for presentation to the viewing user along with the content item. The social networking system may specify an order in which the selected comments are presented based on the interest scores of the selected comments.