Pedagogical content knowledge (PCK) traditionally has been used in research concerning prospective and practicing classroom teachers. This essay argues that PCK is also relevant to other professions including those advancing quantitative reasoning (QR). To illustrate, the case of PCK for teaching QR is considered. Those in fields such as public health, journalism, meteorology, and government increasingly find themselves responsible for helping the public understand an ever-growing amount of quantitative information that has a bearing on societal well-being. Several examples illustrate how such professionals' responsibilities require knowing prevalent QR patterns in society, strategies for fostering sound reasoning, and the general nature of school curricula. Professional organizations in education, colleges of education, and educational researchers would benefit from expanding PCK research to encompass multiple professions. These expanded research and development efforts would simultaneously address urgent societal needs.