This nursing best practice guideline (BPG) is a comprehensive document that provides an overview of principles, resources, and structures for delivering evidence-based supervised injection services (SIS). It is not intended to be a manual or “how-to” guide; rather, it supports best practices and decision-making for nurses, health workers, and health system leaders. This Guideline should be reviewed and applied in accordance with individual SIS facilities and the needs and preferences of persons accessing SIS. This document provides evidence-based recommendation statements and descriptions of (a) pragmatic practice, education, and policy considerations, (b) benefits and harms, and (c) values and preferences. This Guideline predominantly focuses on policy issues related to SIS and highlights relevant supporting documents that directly address clinical practices.