Micro-credentials are increasingly touted as both alternatives and complements to traditional degrees. The term micro-credential has no standard definition. In general, however, many experts agree that a micro-credential shows a mastery of one or more job competencies and is more focused and specialized than a traditional degree. Despite this broad agreement, the details of what micro-credentials are and their role in the credentialing system are highly debated. To assess their potential for building employment opportunities for low-skilled, entry-level workers, the U.S. Department of Labor (DOL) contracted with Mathematica Policy Research to conduct an environmental scan of micro-credentials. Researchers collected information from a literature review, a web search review, and one-on-one interviews with 26 experts and practitioners in the credentialing field. The scan helped define and describe micro-credentials, including what they are and how they are delivered, the opportunities they present and the challenges they generate; their promise for use by the workforce system; and the steps that could be taken to deepen our understanding of their potential to help low-skilled, entry-level workers gain a foothold in the labor market and advance along a career pathway.