Happiness or life satisfaction tends to be the ultimate goal of human beings. It is the intention of this study to investigate the factors influencing the life satisfaction of pro-environment and non-pro-environment people. The data were collected from interviews with 320 adults, who were equally divided into pro-environment and non-pro-environment adults of at least 18 years of age and that had come to the randomly-selected shopping centers in Bangkok. The life satisfaction of the people, regardless of their environmentally-friendly attitude, was assumed to be driven by the personal characteristics of optimism and internal locus of control, and the domains of life of family, personal health, self-actualization, and material possessions, as well as the altruistic and biospheric values of being nature lovers. The results from the t-test suggested that pro-environment people are likely to be more satisfied with their lives than non-pro-environment people. Moreover, the multiple regression analysis indicated that the life satisfaction of the pro-environment people was positively influenced by the biospheric value of being a nature lover, self-actualization, and age, and was negatively influenced by education. The pro-environment people that were never married were more satisfied with their lives than those that were married. Finally, the life satisfaction of the non-pro-environment people was positively triggered by the personal characteristics of optimism and having an internal locus of control, as well as the domain of life of personal health and age.