This paper explores what the first global stocktake (GST1) under the Paris Agreement could usefully do in relation to two elements of its mandate on adaptation, namely, to review the adequacy and effectiveness of adaptation, and to enhance the implementation of adaptation action. This paper also discusses potential outputs from GST1, and how they could facilitate the intended outcomes of the process on adaptation, taking into account a learning-by-doing approach. This paper highlights that a comprehensive collective assessment of the adequacy and effectiveness of adaptation requires data that is currently not available for various reasons. Nonetheless, this paper finds that the GST’s ability to incorporate learning and its scope for continuous improvement provides an important opportunity to develop, apply and refine approaches and methodologies over time to better address the GST’s mandate on adaptation in subsequent cycles. The paper concludes that the GST1 process could help to inform and enhance Parties’ adaptation efforts by identifying priority data needs and gaps, increasing understanding of different approaches to assessing adaptation actions, identifying enabling factors for effective adaptation, and building linkages with parallel processes including on the Global Goal on Adaptation. In this way, the GST1 could play an important role in helping to set a foundation for improved approaches and data on adaptation over time that can feed into future GSTs and support the long-term goals of the Paris Agreement.