This codebook accompanies the Global Gambling Control Scorecard (GGCS) dataset, a comparative tool designed to assess the strength of gambling control systems across countries. The codebook provides detailed definitions, coding instructions, and guidance on interpreting variables within the dataset. It outlines the conceptual framework, domains, and scoring rules used to classify national gambling control policies. Developed through a global e-Delphi study, the GGCS focuses on policies and regulations aimed at preventing gambling-related harms. This document serves as a reference for users analysing or replicating the GGCS dataset and supports transparency and reproducibility of coding decisions.