混鱼龙属（属名：Mixosaurus），意思为“混合蜥蜴”，是种已灭绝双弓类爬行动物，属于鱼龙目。牠们身长约1公尺。混鱼龙分布于全球：中国、帝汶、印尼、意大利、斯匹次卑尔根群岛、司瓦尔巴特群岛、加拿大、阿拉斯加、以及内华达州。牠是在1887年由George H. Baur命名。

混鱼龙的名字来自于牠们的外形介于鳗鱼外形的鱼龙类，例如杯椎鱼龙（Cymbospondylus），以及较晚海豚外形的鱼龙类，例如鱼龙属（Ichthyosaurus），两者之间的过渡性质。混鱼龙拥有长尾巴，尾巴有下鳍，显示牠们游泳速度慢，但同时拥有背鳍，可在水中稳定。混鱼龙每个鳍状肢由五个脚趾构成，较晚的鱼龙属每个鳍状肢由三个脚趾构成。而且每个脚趾的骨头比一般鱼龙类脚趾骨头更为独立（多指性），而前鳍状肢比后鳍状肢还长。

Mixosaurus is an extinct genus of Middle Triassic ichthyosaur. It was the most common genus of Triassic ichtyosaurus: its fossils have been found all over the world, including China, Timor, Indonesia, Italy, Spitsbergen, Svalbard, Canada, as well as Alaska and Nevada in the US. It was named in 1887 by George H. Baur. The name means "Mixed Lizard", and was chosen because it appears to have been a transitional form between the eel-shaped Ichthyosaurs such as Cymbospondylus and the later dolphin-shaped ichthyosaurs, such as Ichthyosaurus. Baur named Mixosaurus as a new genus because its forefin was sufficiently different from that of Ichthyosaurus.