RNA聚合酶（RNA polymerase、RNAP、RNApol、DNA-dependent RNA polymerase，EC2.7.7.6）或称核糖核酸聚合酶，是一种负责从DNA或RNA模板制造RNA的酶。RNA聚合酶是通过称为转录的过程来创建RNA链，以完成这个工程。在科学上，RNA聚合酶是一个在RNA转录本3'端聚合核糖核甘酸的核苷转移酶。RNA聚合酶是一种非常重要的酶，且可在所有生物、细胞及多种病毒中可见。

RNA聚合酶是于1960年分别由山姆·怀斯及霍维兹同时发现。但在此之前，于1959年，诺贝尔奖颁发给了塞韦罗·奥乔亚，因为他的发现当时认为是RNA聚合酶，但其实是核糖核酸酶。

RNA polymerase (RNAP or RNApol) (Ribonucleic acid), also known as DNA-dependent RNA polymerase, is an enzyme that produces primary transcript RNA. In cells, RNAP is necessary for constructing RNA chains using DNA genes as templates, a process called transcription. RNA polymerase enzymes are essential to life and are found in all organisms and many viruses. In chemical terms, RNAP is a nucleotidyl transferase that polymerizes ribonucleotides at the 3' end of an RNA transcript.