<p>Empirical research has demonstrated that both the virtue of humanity and social environment contribute to happiness. Practical experience further indicates that the possession of virtues is insufficient for achieving happiness, which depends on external conditions. However, few studies have examined the combined effect of humanity virtues and social environment on children’s happiness. This study explored the relationships between the virtue of humanity and happiness and the role of the social environment among children in the Chinese culture. Participants were 3289 children in grades 4–6 in a Chinese city following a child-friendly paradigm and were selected by a multistage cluster sampling method. All of the children completed a survey of their demographic information, psychology, and the social environment in which they lived. Love, kindness, and social intelligence were positively associated with children’s happiness (Model 1). Compared to Model 1 that included only the virtue of humanity, Model 2 added the friendly social environment variables and increased the explanatory power of children’s happiness (R²) by 14.82%, from 34.89 to 49.71%, showing that a friendly social environment moderates the effect of the virtue of humanity on happiness. The relationships between the virtue of humanity and happiness varied among social environments with high, moderate, and low friendliness. The findings indicate that the virtue of humanity is positive related with children’s happiness, and friendly social environments foster such relationships. Accordingly, to achieve the goal of children’s happiness, it is essential to focus on both virtue education and the creation of a child-friendly social environment.</p>