行政主导，指政治架构中行政部门（政府）主导政治议题和立法的情况。

出现这样的词语主要是为了和西方国家的三权分立论抗衡，以论证中国式政府存在的合理性。

虽然香港和澳门的基本法从未提到「行政主导」四字，但中央政府、学者或传媒经常以此形容两个特区的政治体制。

在回归前，与大部份英国殖民地一样，香港总督长期兼任立法部门（立法局）主席，对所有法案、议案有最终否决权。直至最后一任港督彭定康于1993年设立主席一职，港督才不再参与立法局事务。主权移交后，行政长官沿袭旧制，不再兼任立法部门主席，但被刻意设计成行政部门对立法部门（香港立法会）的制衡力较大。主要有三方面：

An "elective dictatorship" (also called executive dominance in political science) is a phrase popularised by the former Lord Chancellor of the United Kingdom, Lord Hailsham, in a Richard Dimbleby Lecture at the BBC in 1976. The phrase is found a century earlier, in describing Giuseppe Garibaldi's doctrines, and was used by Hailsham (then known as Quintin Hogg) in lectures in 1968 and 1969. It describes the state in which Parliament is dominated by the government of the day. It refers to the fact that the legislative programme of Parliament is determined by the government, and government bills virtually always pass the House of Commons because of the nature of the majoritarian first-past-the-post electoral system, which almost always produces strong government, in combination with the imposition of party discipline on the governing party's majority, which almost always ensures loyalty. In the absence of a codified constitution, this tendency toward executive dominance is compounded by the Parliament Acts and Salisbury Convention which circumscribe the House of Lords and their ability to block government initiatives.