海牙（荷兰语：Den Haag；dɛnˈɦaːx），官方亦称s-Gravenhage（ˈsxraːvə(n）ˌɦaːɣə）是荷兰第三大城市，在阿姆斯特丹和鹿特丹之后，人口48万5千人（2009年5月31日），大海牙地区人口约101万人，面积约100平方公里。海牙位在西荷兰的南荷兰省，同时也是该省省会。鹳鸟徽是海牙的市徽。

因荷兰的宪法规定首都是阿姆斯特丹，所以海牙并不是荷兰的首都，但它是中央政府所在地，而且贝娅特丽克丝女王也居住在海牙并于此办公。所有的中央政府机关与外国使馆几乎都位于此，另外最高法院与许多组织也都在此办公，例如荷兰城市自治协会VNG。

The Hague (/ðə ˈheɪɡ/; Dutch:Den Haag pronounced[dɛnˈɦaːx] or 's-Gravenhage pronounced[ˈsxraːvə(n)ˌɦaːɣə]) is the seat of government in the Netherlands, and the capital city of the province of South Holland. With a population of 515,880 inhabitants (as of 1 January 2015) and more than one million inhabitants including the suburbs, it is the third largest city of the Netherlands, after Amsterdam and Rotterdam. The Rotterdam The Hague Metropolitan Area, with a population of approximately 2.7 million, is the 12th-largest in the European Union and the most populous in the country. Located in the west of the Netherlands, The Hague is in the centre of the Haaglanden conurbation and lies at the southwest corner of the larger Randstad conurbation.