Objective: The objective of this study is the analysis of the ABNT NBR ISO 14001:2015 standard - Environmental Management Systems in organizations of the Electricity Sector as a strategic tool to answer the Environmental Questionnaire of the Corporate Sustainability Index (ISE B3 - main index for the evaluation of ESG practices in the Stock Exchange.   Theoretical Framework: The theoretical framework of this work is based on fundamental concepts of ESG (Environmental, Social and Governance), Environmental Management Systems and Corporate Sustainability. In addition, the research considers the hypothesis of the correlation between the implementation of ISO 14001 and a better performance in ISE B3. Stakeholder Theory and Corporate Social Responsibility Theory are relevant to understanding why companies should adopt sustainable practices and how this can influence their performance and reputation.   Method: The methodology adopted for this research was qualitative, characterized as exploratory. A comparative documentary study was carried out between the requirements of ISO 14001 and the Questionnaire of the Environment Dimension of the Corporate Sustainability Index. The conformity and correlation between the items of ISO 14001 and the questions of the ISE B3 Questionnaire were evaluated, weighting them in three degrees of applicability.   Results and Discussion: The results obtained highlight the strong correlation between ISO 14001 certification and compliance with the ISE B3 Questionnaire in the Environmental Dimension. In addition to adding value to operations and maintenance on environmental issues, ISO 14001 certification provides companies in the electricity sector with a competitive advantage by obtaining higher scores in sustainability indices. The adoption of an ISO 14001 certified Environmental Management System provides a structured path to environmental alignment and the incorporation of environmental management into the corporate sustainability strategy.   Research Implications: The practical and theoretical implications of this research highlight the importance of ISO 14001 certification as a strategy to meet the environmental demands of the financial market, highlighting the need to consider environmental, social and governance aspects for holistic business management in the electricity sector. These implications can encompass ISO standards and ESG criteria, environmental and business standards, as well as providing practical guidance for companies in formulating strategies that improve their performance and financial reputation.   Originality/Value: This study contributes significantly to the research by presenting an innovative approach in the analysis of the ABNT NBR ISO 14001:2015 standard and its impact on the response to the Environmental Questionnaire of the Corporate Sustainability Index in the Electricity Sector. The results provide valuable insights into how Generation and Transmission companies can improve their environmental performance and sustainability index scores. It broadens the understanding of the practical applicability of ISO 14001 in the specific context of the financial market, positively impacting the area of study and professional practices in the field of corporate sustainability. Las variables ambientales, sociales y de gobierno (ESG) continúan creciendo en relevancia académica e industrial. Estas variables son motores de los negocios del Sector Eléctrico y agenda obligada en las discusiones en el mercado financiero. Especialmente en temas ambientales que ocupan un lugar históricamente destacado en las empresas de Generación y Transmisión. Este trabajo se centra en el análisis de la norma ABNT NBR ISO 14001: 2015 - Sistemas de Gestión Ambiental en las organizaciones del Sector Eléctrico como herramienta estratégica para responder al Cuestionario Ambiental del Índice de Sostenibilidad Empresarial (ISE B3 - el principal índice para evaluar las prácticas ESG en la Bolsa de Valores.La metodología es cualitativa, caracterizada como exploratoria.Se realiza a través del análisis documental de un cuadro comparativo y definición de grados de aplicación (alto, medio, bajo) de los requisitos de la norma ISO 14001 en respuesta al Medio Ambiente del ISE. Dimensión Cuestionario B3 Los resultados revelaron que el cumplimiento de los requisitos de la ISO 14001 tiene una fuerte y significativa correlación con las mejores respuestas al Cuestionario ISE B3 - Dimensión Medio Ambiente Identificamos la relevancia de la aplicabilidad de la ISO 14001 tanto en el análisis general como por temas ambientales de las preguntas que componen el Cuestionario, además de generar valor para la operación y mantenimiento de organizaciones en temas ambientales, la norma ISO 14001 brinda una buena propuesta para que las empresas de Generación y Transmisión obtengan mejores puntajes en los índices de sustentabilidad que miden las prácticas ESG.