Buddhism is one of the oldest major religions in the world, with its roots tracing back to the fifth century BCE, and came into being when Buddha Gautama reached enlightenment, delivering his first teaching more than 2500 years ago. Buddhism has spread throughout Asia and into the Western world, currently practiced by approximately 7% of the world’s population. Through centuries of development, spread, and evolution, it has influenced and become infused with various social, cultural, philosophical, and scientific traditions. At the common core of Buddhism lies the Four Noble Truths, which guide the liberation from suffering towards enlightenment. This includes letting go of cravings and attachments, gaining perception into the true nature of things, and following the eightfold path encompassing moral virtues, meditation, and wisdom. Key concepts also include the Middle Way, not falling into the traps of dualism and extremism, and Dependent Origination, deep insight into the true interdependent nature of all existence and nonexistence.Western psychological adoption of Buddhism tends to focus mostly on secular and circumscribed aspects that have immediate applicability to perceived psychological needs, such as reducing stress, regulating emotions, and achieving mental well-being. Some of the principles and practices, such as mindfulness, are increasingly being integrated into various forms of psychotherapy, from psychodynamic therapy to third-wave therapies such as mindfulness-based stress reduction, mindfulness-based cognitive therapy, dialectical behavioral therapy, and acceptance and commitment therapy (ACT). A deeper understanding of key Buddhist concepts can further inform the practice of psychotherapy, as illustrated by a case in this chapter. Mental health practitioners, regardless of discipline and background, may find benefits in exploring the integration of Buddhist wisdom into their personal lives and professional practice. On a societal level, Buddhist perspectives may promote wider social engagement and activism.