Contemporary interest in STEM education is fueled, in part, by the poor performance of U.S. students on national and international assessments. According to a recent National Research Council (2011) report on STEM education in the United States, the National Assessment of Educational Progress (NAEP) indicates that approximately 75% of U.S. 8th graders are not proficient in mathematics when they complete 8th grade, and, despite some progress over time, significant achievement gaps between racial and socioeconomic status subgroups persist in NAEP performance. Performance data also typically indicate lower levels of average performance in mathematics and science for U.S. students than for their counterparts in other countries with whom the United States competes in the global marketplace of commerce and information. The central premise of this article is that at least one international assessment of mathematics and science, the Programme for International Student Assessment (PISA), is valuable for reasons that go well beyond its use as a source of data; it sounds the alarm about low U.S. student achievement and, thus, motivates greater attention to STEM education. If used appropriately, PISA can help promote the professional learning of U.S. teachers, thereby improving STEM teaching and learning in this country. PISA's focus on literacy--the ability to use and apply knowledge and skills to real-world situations encountered in adult life--in mathematics and science is aligned with STEM literacy and thus appears to be exactly the right emphasis to achieve the "STEM for All" goal. In this article, the authors focus primarily on the STEM discipline of mathematics, but they contend that their proposal that PISA can be a valuable tool to support this endeavor also could be applied to the science and engineering domains of STEM, and they invite interested readers to consider that possibility.