Due to the risky nature of the movie market, production companies increasingly rely on sequel movies to generate box office revenues. Existing research has examined various driving factors behind the success of sequel movies. However, researchers have paid limited attention to the impact of the content and variation in reviews of the parent movies on the box office success of sequel movies.This paper conducts an empirical analysis based on data from 150 sequel movies released in China from 2014 to 2018. Using machine learning-based text analysis methods, we measure the diversity of reviews for the parent movies and find a significant positive effect of review diversity on the box office performance of sequel movies. Additionally, we verify the role of information richness as the underlying mechanism. Specifically, the more reviews a parent movie receives, the stronger the positive impact of review diversity on the box office performance of its sequel movies. The number of media reports and the duration of sequel movies in theaters negatively moderate the main effect. This study extends the research on the movie market and provides a new perspective for firms to consider word-of-mouth factors for marketing sequel movies, thus offering important managerial implications.