This paper provides a critical review of public sector innovation measurement approaches and related gaps. It explores alternative approaches to measure public sector innovation measurement which respond to different use cases, and paves the way for operationalising a measurement framework for public sector innovation. The paper proposes creating a continuous stocktake of public sector innovation measurement activities in Member countries, improving existing frameworks or creating new frameworks to guide public sector innovation measurement more systematically at country level, and identifying indicators that would be most useful for cross-country comparability.