Techniques are described for enabling users of a certificate management service to create certificate issuance policies that can be applied to certificate issuance requests across both public and private certificate authorities (CAs) and other certificate-related services. According to embodiments described herein, a certificate issuance policy includes one or more certificate issuance rules to be applied to requests associated with one or more specified user accounts or roles for certificate-related resources (e.g., public certificates, private certificates, etc.). The application of a certificate issuance rule can be conditioned on a particular request context (e.g., based on a user account or role associated with a request, a type of certificate requested, a subject name identified in the request, etc.) and can specify a wide range of actions to be performed on requests matching a rule (e.g., allowing or denying a request, modifying one or more parameters of the request, etc.).