The aggressive growth of cloud computing has brought with it a challenge to balance strong cybersecurity with environmental stewardship. Though necessary for security, conventional cloud security strategies, ranging from 24/7 monitoring to energy-hungry AI analytics, guzzle enormous amounts of energy and generate high carbon emissions. This chapter, “Green Cybersecurity,” addresses this challenge head-on. It extends beyond just acknowledging the challenge by examining an emerging paradigm in which security and sustainability are not competing goals but complementary ones. We get into actual-world, state-of-the-art solutions like energy-efficient AI and machine learning algorithms, cloud-native systems that waste nothing, and effective data processing practices. By embedding green responsibility into the core of our cyber defenses, we can design security systems that are not only better and more intelligent but also sustainable in the long run. It’s not a compromise; it’s about securing our future by making security smarter, efficient, and responsible.