A social dilemma is a situation in which people face a conflict between maximizing personal interest (noncooperation) and maximizing collective interest (cooperation). Although a noncooperative choice leads to a better individual outcome, when all people do the same, all will be worse off than if all choose to cooperate. Climate “Code Red,” overpopulation, funding for public television, and the depletion of scarce and valuable resources such as forests and fisheries are all typical examples of social dilemmas. A long-lasting theme in the research into social dilemmas is the identification of effective approaches to induce voluntary cooperation. In the past five decades, many strategies have been discovered, with communication, sanction, emotion, and norm formation being the most effective ones. Meanwhile, a personality trait called social value orientation (SVO) demonstrated its stable predictive power of human cooperation in social dilemmas. A close examination of the effects of the strategies and SVO reveals several distinct and common underlying psychological mechanisms, namely, group identity, cooperative norm, expectation of others’ cooperation, and interpersonal trust. These strategies and mechanisms have important implications for future research into social dilemmas because in the age of digitization and social distancing, new forms of social dilemmas that pose enormous challenge to human existence such as online teamwork and organization, global warming, and COVID-19, are emerging and calling for solutions.