This chapter discusses stress and its effects on health from a psychological perspective. It defines stress as the body's nonspecific response to demands, and identifies major sources of stress including life changes, chronic stress, job stress, and conflicts. Prolonged stress can impair the immune system and increase disease risk via activation of the sympathetic nervous and HPA axes. Personality traits like Type A and hardiness also impact health. The chapter then covers health psychology and managing stress through problem-focused and emotion-focused coping, as well as lifestyle resources like exercise, social support, and relaxation.