Livestock is known to contribute significantly to climate change and to negatively impact global nitrogen cycles and biodiversity. However, there has been little research on economically efficient policies for regulating meat production and consumption. In the absence of first-best policy instruments for the livestock sector, second-best consumption taxes on meat can address multiple environmental externalities simultaneously as well as improve diet-related public health. In this article, we review the empirical evidence on the social costs of meat and examine the rationales for taxing meat consumption in high-income countries. We approach these issues from the perspective of public, behavioral, and welfare economics, focusing in particular on (1) the interaction of multiple environmental externalities of meat production and consumption, (2) “alternative protein” technologies, (3) adverse effects on human health, (4) animal welfare, and (5) distributional effects of meat taxation. We present preliminary estimates of the environmental social costs associated with meat consumption and find that meat is significantly underpriced. We conclude by identifying several directions for future research on optimal meat taxation.