罗伯特·安森·海莱恩（英语：Robert A. Heinlein，1907年7月7日－1988年5月8日），美国硬科幻小说作家，被人称为科幻先生（Mr. SF）。

他的作品不但在科学和工程方面的可信性达到了罕有的标准，而且也提高了科幻类的文艺水平评价标准。他是1940年代晚期将无修饰科幻小说打入主流一般杂志（比如《星期六晚邮报》）的第一位科幻小说作家，他是1960年代最畅销长篇科幻小说的前几名作家之一。与另外二位作家艾萨克·阿西莫夫、阿瑟·克拉克并称为科幻小说三巨头。赢得五次星云奖，于1975年获得星云奖第一届科幻大师奖、七次赢得雨果奖（其中三次为追授）。

Robert Anson Heinlein (/ˈhaɪnlaɪn/; July 7, 1907 – May 8, 1988) was an American science fiction writer. Often called the "dean of science fiction writers", he was an influential and controversial author of the genre in his time.

He was one of the first science fiction writers to break into mainstream magazines such as The Saturday Evening Post in the late 1940s. He was one of the best-selling science fiction novelists for many decades, and he, Isaac Asimov, and Arthur C. Clarke are often considered to be the "Big Three" of science fiction authors.