In Islam, moral responsibility which means accountability for moral duties does not make sense when it is disconnected from God. The most important issue about moral responsibility is that which deals with its theoretical foundations. These foundations include anthropological, ontological, epistemological, axiological, and sociological foundations.The present paper aims at investigating the sociological origin of man's moral responsibility. The foundations which are worth mentioning here are man's sociability, individualism, conventionality of society, interaction between individual and society, regularity of social affairs. The principle of man's moral responsibility can be demonstrated and then explained by referring to the foundations and to such things like moral duty, moral right and its correlation with duty and the correlation between duty and responsibility. First, the foundations related to responsibility have been extracted. Then an argument based on these foundations is advanced. The research is based on an analytical-rational method, a library survey and demonstrative argumentation.