环辛烷（化学式：C₈H₁₆）是八个碳的环烷烃。

无色液体或潮湿的白色固体。有类似樟脑的气味。难溶于水，易溶于乙醇、乙醚、苯等有机溶剂。易燃。

Cyclooctane is a cycloalkane with the molecular formula (CH₂)₈. It is a simple colourless hydrocarbon, but it is often a reference compound for saturated eight-membered ring compounds in general.