This primer responds to central banks' growing demand for knowledge on social, governance, and environmental considerations (ESG) in the investment process. This area has gained traction in the last two decades. More recently, central banks' interest in ESG has increased, but much of the information available is aimed at investors with different investment objectives and broadly diversified portfolios. The authors fill that information gap by reviewing the definitions of ESG and the main ESG investment approaches, including their applicability to asset classes. The authors then examine how foreign reserve managers can apply ESG investing in their reserve management operations. The authors find limited scope for implementing ESG strategies in reserve management, given that most central banks still invest primarily in sovereign bonds of major economies. Yet, the authors also identify opportunities and critical considerations for central banks interested in implementing ESG investing in their reserve management operations.