Investors increasingly commit to consider environmental, social, and governance (ESG) factors in their investment decisions. However, the challenges of investors for a holistic integration of ESG factors in their investment decisions are manifold and endanger reaching urgent societal goals. The paper uses metasynthesis to develop a comprehensive understanding of these impediments from a diverse set of papers. Supported by textual analysis, it identifies 161 different topics, which are subsumed within groups and aggregated along a four-pillar framework of market-, firm-, regulatory-, and individual-based impediments. The most prominent impediments are found in the areas of a perceived lack of a business case, the quality of data, the absence of clear standards and definitions, and various behavioral biases.Moreover, a considerable research-practice gap in framing the relevant research questions that contribute to the slow-moving integration process is discovered.Focusing additionally on potential blind spots on the investor and research sides will prove to be important for swifter ESG integration.