ABSTRACT This article discusses the law, context, culture, and practice behind the Presiding Officer’s certificate in the Scottish Parliament. In doing so, it uncovers the importance of Westminster parliamentary culture in Scottish governance. The Presiding Officer’s certificate, which indicates whether the Presiding Officer believes that legislation is within the Scottish Parliament’s competence, sits uncomfortably with Scottish parliamentary culture. The certificate is similar to procedures in Nordic parliaments, but not Westminster-style parliaments. When this procedure came under pressure, the importance of Westminster parliamentarism in Holyrood became clear. The certificate is compared to the Commons Speaker’s role under English Votes for English Laws. Scotland is still learning to harmonise its institutions with its parliamentary culture.