Triazabicyclodecene (1,5,7-triazabicyclo[4.4.0]dec-5-ene or TBD) is an organic compound consisting of a bicyclic guanidine.

For a charge-neutral compound, it is a relatively strong base that is effective for a variety of organic transformations.

TBD is colorless solid that is soluble in a variety of solvents.

[8] Deprotonation at the 7-position gives a particularly electron-rich ligand as manifested in the redox properties of ditungsten tetra(hpp).

The conjugate acid of TBD is the preferred cation among the guanidinium hypoiodites, which are specialized oxidizing agents for various types of organic compounds.