西门子股份公司（SIEMENS AG(德语发音：[ˈziːmɛns]））是德国的跨国企业，在电机和电子领域是全球业界的先驱，活跃在能源、医疗、工业及基础建设与城市四大业务领域。此外，西门子也是美国《财富》杂志2015年评选的全球最大500家公司的排行榜中的第63名。西门子于1847年由维尔纳·冯·西门子创建，总部位于德国慕尼黑。西门子股份公司是在法兰克福证券交易所和纽约证券交易所上市的公司。

西门子目前在全球拥有约405,000名员工，公司业务遍布190个国家。

Siemens AG (German pronunciation:[ˈziːmɛns]) is a German company headquartered in Berlin and Munich and the largest engineering company in Europe with branch offices abroad.

The principal divisions of the company are Industry, Energy, Healthcare, and Infrastructure & Cities, which represent the main activities of the company. The company is a prominent maker of medical diagnostics equipment and its medical health-care division, which generates about 12 percent of the company's total sales, is its second-most profitable unit, after the industrial automation division. The company is a component of the Euro Stoxx 50 stock market index. Siemens and its subsidiaries employ approximately 362,000 people worldwide and reported global revenue of around €71.9 billion in 2014 according to their annual report.