The Paris Agreement establishes a Global Stocktake to facilitate a periodic review of parties’ collective progress towards achieving global climate change goals, as a prelude to parties submitting enhanced “nationally determined contributions” (NDCs). The Stocktake’s success in facilitating greater ambition may be critical to the ultimate effectiveness of the Paris Agreement. Given the unique nature and purpose of the Global Stocktake, existing review mechanisms in other international regimes offer only limited insight to help inform its design. Its key differentiating features are its underlying aim—increasing ambition over time—and its exclusive focus on collective rather than individual performance. This policy brief outlines unique features of the Global Stocktake that make it, potentially, a true innovation in global governance. Highlighting six design issues—purpose, object, sources and types of inputs, collective learning, especially concerning the practice of “doing transformations,” and goal psychology—the brief draws lessons from existing international regimes and identifies opportunities for innovation in global governance in the design of the Global Stocktake.