Tricyclohexylphosphine is the tertiary phosphine with the formula P(C<sub>6</sub>H<sub>11</sub>)<sub>3</sub>. Commonly used as a ligand in organometallic chemistry, it is often abbreviated to PCy<sub>3</sub>, where Cy stands for cyclohexyl. It is characterized by both high basicity (pK<sub>a</sub> = 9.7) and a large ligand cone angle (170ð).
Important complexes containing P(Cy)<sub>3</sub> ligands include the 2005 Nobel Prize-winning Grubbs' catalyst and the homogeneous hydrogenation catalyst Crabtree's catalyst.