The American Library Association (ALA) reported an "unprecedented" number of book challenges in 2022 (ALA, 2022b), resulting in nationwide media coverage and increased awareness of censorship attempts. However, these numbers represent only censorship attempts from external entities, such as parents and the general public; some librarians engage in censorship themselves in the form of self-censorship. This mixed-methods study examined the extent to which the recent increase in book challenges and bans has influenced the self-censoring behaviors of school librarians when selecting books for their collections and the controversial topics they are most hesitant to include in their library collections. Findings indicate that although the majority had never experienced a challenge, participants expressed increased hesitancy to add books potentially perceived to contain controversial material and that they weighed the effects of controversial subject matter more often in the most recent year compared to previous years. Despite the nationwide increase in challenges, few had revised their collection development policies. Topics and book characteristics they are most hesitant to add to their collections include sexual content, abortion, profanity, and self-harm/suicide. Participants who had not experienced a challenge were less likely than those who had experienced a challenge to purchase materials with potentially controversial topics, particularly books with sexual content or LGBTQIA+ characters.