The increasing reliance of modern society on energy consumption highlights the crucial need for a reliable, secure, and affordable energy supply. However, climate change poses significant risks to the energy sector, impacting fuel supply, energy production, physical resilience of infrastructure, and energy demand. To ensure the continued delivery of reliable performance in the face of extreme climatic conditions caused by global warming, resilience planning and strategic investments are essential. Energy security is another pressing challenge, particularly for countries heavily dependent on energy imports. For instance, the European Union relies on Russia for approximately 40% of its natural gas and petroleum products consumption. Consequently, achieving high resilience in energy systems becomes paramount for societies that heavily rely on continuous access to energy services. This chapter provides an overview of the complex terminologies associated with energy system resilience, encompassing non-standardized definitions, the influence of climate change and weather events, different domains of energy system resilience, and approaches to enhancing resilience in energy systems. By exploring these aspects, the chapter aims to contribute to a deeper understanding of energy system resilience and the strategies required to ensure the long-term sustainability and stability of energy supply in the face of climate change challenges.