Critics have regarded Transformations (1974) as a turning point in Anne Sexton's poetic canon, because it utilizes a narrative framework and engages extensively with humor. Though Sexton admired Kurt Vonnegut's Slaughterhouse-Five (1969) and convinced him to write the foreword for her collection, critics have yet to note the impact of his influence. This article argues that Vonnegut's influence on Sexton's humor is twofold. First, Sexton draws from Vonnegut in the craft of her humor—her poetic lines utilize specifically Vonnegut-esque techniques. Second, Sexton's collection uses Vonnegut's understanding of humor as it relates to trauma, mimicking his use of multiple perspectives and concept of time travel in Slaughterhouse-Five. Ultimately, Sexton draws from Vonnegut's understanding of humor in order to subtly embolden the confessional claims in her poetry, embracing a new way of writing that broadened her ability to speak to human suffering.