Cycloundecane is a saturated cyclic organic compound with eleven carbon atoms forming a ring. It is classed as an alkane because it has only carbon and hydrogen and these elements are configured with C–H and C–C such that there is a chain of carbon atoms with hydrogens attached to them. For each of the carbon atoms in the chain there is a pair of hydrogen atoms such that the chemical formula is C₁₁H₂₂. The compound is stable, but it burns with sufficient ignition heat.

Variants of this compound, for example, bicycloundecane, have been proposed for use in conductors for electronic circuitry.