御准又称王室同意（英语：Royal Assent），是指立宪君主正式批准并颁布其国家议会法案，由此创建法律的进程。对绝大多数的现代君主政体而言，御准仅是一项例行进程；但即使在统治者仍有权拒绝授予御准的国家（例如英国、挪威和列支敦士登），统治者也甚少动用此权，而是遵从其政府的决策，以免陷国家于可怕的政治危机中（参见保留权）。欧洲君主政体对否决权的行使曾实为频繁；但自18世纪发展出现代民主政治氛围后，拒授御准的情形已极为少见。

御准通常是以英皇制诰等较为书面的方式进行授予，有时也会伴随着详尽仪式。例如在英国，上议院专员在经君主任命后，负责在西敏宫的典礼上宣布批予御准。在其他国家，如澳大利亚和加拿大，仅由总督签署法案。然而，无论是御准方式为何，议会在事后必须获知御准；此可以由两种途径：上议院专员或君主的代表在各议院在场时公开授予御准；或者个别通知议院，对象通常是该议院议长。

Royal assent is the method by which a country's constitutional monarch (possibly through a delegated official) formally approves an act of that nation's parliament, thus making it a law or letting it be promulgated as law. In the vast majority of contemporary monarchies, this act is considered to be little more than a formality; even in those nations which still permit their ruler to withhold the royal assent (such as the United Kingdom, Norway, and Liechtenstein), the monarch almost never does so, save in a dire political emergency or upon the advice of their government. While the power to withhold royal assent was once exercised often in European monarchies, it is exceedingly rare in the modern, democratic political atmosphere that has developed there since the 18th century.