We examine recent evidence on the consequences of selfishness and otherishness for psychological well-being, physical health, and relationships. In the first sections, we consider recent evidence regarding the costs and benefits of giving time, money, and support to others and the costs and benefits of taking or receiving those things from others. Then, because the behaviors of giving and taking can be motivated either by selfish or otherish concerns, we next consider the costs and benefits of the motivation underlying giving and taking. We also examine why and for whom selfishness and otherishness have consequences for psychological well-being, physical health, and relationships. We focus on mechanisms identified in research, including intrapsychic mechanisms such as positive and negative affect, self-esteem and self-efficacy, a sense of meaning and purpose in life, and a sense of connectedness to or isolation from others, as well as interpersonal processes such as reciprocation of support and responsiveness.