Is sustainability a megatrend? If so, what does it mean to be a megatrend, and how can macromarketing advance our understanding of sustainability as a megatrend? This article makes three contributions to research on sustainability as megatrend. First, if offers a set of elemental criteria to understand the concept of a megatrend. Megatrends are complex in nature, whose understanding requires the skills and perspectives of macromarketers. Second, this article articulates two schools of thought in Macromarketing scholarship, a Developmental School and a Critical School. The former operates from the premise that marketing systems are important parts of the solution to the human condition, while the latter operates from the premise that they are part of the problem. Each concludes that sustainability is the megatrend of our time, but for different reasons. Finally, this article offers directions for macromarketing scholars, who are uniquely positioned to explore sustainability as megatrend.