Tebbe's reagent is the organometallic compound with the formula (CH)TiCHClAl(CH). It is used in the methylidenation of carbonyl compounds, that is it converts organic compounds containing the RC=O group into the related RC=CH derivative. It is a red solid that is pyrophoric in the air, and thus is typically handled with air-free techniques. It was originally synthesized by Fred Tebbe at DuPont Central Research.
Tebbe's reagent contains two tetrahedral metal centers linked by a pair of bridging ligands. The titanium has two cyclopentadienyl (, or  Cp) rings and aluminium has two methyl groups. The titanium and aluminium atoms are linked together by both a methylene bridge (-CH-) and a chloride atom in a nearly square-planar (Ti–CH–Al–Cl) geometry.  The Tebbe reagent was the first reported compound where a methylene bridge connects a transition metal (Ti) and a main group metal (Al).