Many research have been presented that altruism and social support is related with happiness. Though altruism and social support of factors which is influential to happiness is an important variable, investigation about the relevance between them was not done a lot of research. Therefore this study confirms that influence elementary’s altruism and social support effects for happiness, also investigate the mediating effect of social support in the relationship between elementary’s altruism and happiness. Results were based on a sample of 340 children age 11 to 12 years. Data were collected by using a scale of happiness, helping behavior measures, the social support scale with make out a one list. The collected data was performed correlation analysis and frequency analysis by IBM SPSS 19.0 and analyzed the structural equation modeling by AMOS 21.0. Analysis Results showed happiness and altruism, social support is significantly correlated between all the variables. The results also confirmed that the social support have a significant part of the mediating effect when altruism affects the impact on happiness discussed the mediating effect of social support in elementary’s altruism and happiness. This study confirmed that elementary’s altruism affects happiness positively, child with high altruism the more highly recognizes a social support, child who is receiving social support is altruism. Also this study confirmed that social support has a significant part of the mediating effect when altruism affects happiness. This study suggests that systematically support and education about altruism and social support is important for improving elementary s happiness.