Blockchain technology has evolved from a niche subject to the hottest tech disruption buzzword, but there is still a lot of confusion about the subject. Without a clear understanding about what Blockchains are, their potential public sector potential impact is sometimes misunderstood or, more often, ignored. Questions related to their technical complexity, risk, security, and appropriateness often serve as obstacles to government officials’ ability to truly engage with this emerging technology. In light of this, the Observatory of Public Sector Innovation (OPSI) in collaboration with the Working Party of Senior Digital Government Officials (E-Leaders) has developed a guide on Blockchains and how they may (and may not) apply to government. OPSI is part of the OECD Directorate for Public Governance (GOV).