Curricular guidelines promote standardized approaches to coverage of essential knowledge and skills in undergraduate education. The American Society for Microbiology (ASM) Curriculum Guidelines for Undergraduate Microbiology were developed in 2012. Continuous, rapid growth of knowledge in science and a dynamic, changing world necessitate updates to these guidelines. As such, ASM formed a task force in the summer of 2022. The task force assessed the 2012 ASM Curriculum Guidelines considering advancements in technology, an understanding of an expanded role of microbes, and a broader scope addressing relevant social and environmental aspects of microbiology. Language in the updated guidelines was also modified to better include eukaryotic microbes, viruses, and other acellular microbes. The task force formed working groups, each aimed at revising specific sections of the 2012 ASM Curriculum Guidelines. The revisions to the ASM Curriculum Guidelines were reviewed by subject matter experts and education stakeholders. Feedback from this peer review was incorporated into the updated guidelines, and further comments were solicited from the ASM Conference of Undergraduate Educators (ASMCUE) attendees in November 2023 before these guidelines were finalized. In this article, we describe the rationale and development of updated ASM Curriculum Guidelines which identify foundational concepts that will serve to improve microbial literacy and that can be expanded upon to address more advanced and specialized topics.