国民经济核算（英语：system of national accounts）（或“国民经济会计制度”；system of national accounts，缩写：SNA）指使用完整、一致的财会核算办法量化一国或一地区的所有经济活动。SNA核算体系能够全面反映一国、一地区经济发展状况，SNA为最早源自市场经济发育完善的欧美地区使用的核算体系，也称之为“西方体系”。**、港澳地区引入较早，中国大陆自1992年完整引入该核算体系，取代之前的《国民经济平衡表体系》（MPS），并与联合国国民经济核算体系（UNSNA）接轨。

National accounts or national account systems (NAS) are the implementation of complete and consistent accounting techniques for measuring the economic activity of a nation. These include detailed underlying measures that rely on double-entry accounting. By design, such accounting makes the totals on both sides of an account equal even though they each measure different characteristics, for example production and the income from it. As a method, the subject is termed national accounting or, more generally, social accounting. Stated otherwise, national accounts as systems may be distinguished from the economic data associated with those systems. While sharing many common principles with business accounting, national accounts are based on economic concepts. One conceptual construct for representing flows of all economic transactions that take place in an economy is a social accounting matrix with accounts in each respective row-column entry.