The grotesque is an effective tool for conveying contrasting human emotions to the audience. It encompasses concepts such as exaggeration, horror, and the distortion of reality. Among the most prominent contemporary theorists in this field are Mikhail Bakhtin and Harold Bloom. Through their extensive research, innovative and critical interpretations, and creation of well-known literature on the grotesque, they are considered influential figures in this domain. In Iranian dramatic literature, the concepts of the grotesque have been utilized in the works of a few writers, including Bahram Beyzai, who wrote plays with this theme during the 1960s and 1970s. The success of grotesque and critical plays in the West, the unstable social and political conditions in Iran during that period, the trivialization of humor in Iranian theater, and the failure to engage the audience may have provided the impetus for writers like Bahram Beyzai to write plays with a critical and reformative approach under the umbrella of the Western grotesque. Among Beyzai's works in this regard is the play ‘Chahar Sandough’ (Four Boxes) (1967). How the critical concept of the grotesque and its components have been used in Iranian plays such as ‘Chahar Sandough’ is a topic that has received little attention so far. This research, using library resources and relying on a descriptive-analytical approach, seeks to examine the theoretical foundations and critical functions of grotesque humor in Bahram Beyzai's ‘Chahar Sandough,’ based on the teachings of Harold Bloom and Mikhail Bakhtin. The findings of the study show that Bakhtin and Bloom's grotesque elements, such as humor, exaggerated laughter, and satire, are employed in ‘Chahar Sandough,’ and through these, Bahram Beyzai has been able to effectively present his critical and reformative ideas about the social structure of Iran during his time.