The need to adapt to climate change is undisputed, as evidenced by the increasing commitments being made to adaptation. Despite the recognized need, there are significant challenges that make it very difficult to track, monitor, and evaluate adaptation. There is no “one size fits all” approach; instead, what adaptation looks like varies depending on the context and scale. Because climate change is evolving and will continue to evolve, adaptation is also not a one-time action or endpoint, but rather a process (or an adaptation pathway) that requires adaptive management as new information comes to light. The future trajectory of climate change also makes it difficult to judge when adaptation has been successful, as the consequences of today’s actions often become apparent only after climate conditions have changed. Adaptation also involves value judgments that reflect risk tolerance and trade-offs. Taken together, these factors mean that adaptation defies typical metrics. This document provides an overview of the challenges and current approaches to climate adaptation measurement, as well as guiding principles and their real world application for program implementation and monitoring.