Tetramethylguanidine is an organic compound with the formula HNC(N(CH3)2)2.

This colourless liquid is a strong base, as judged by the high pKa of its' conjugate acid.

[2] It was originally prepared from tetramethylthiourea via S-methylation and amination, but alternative methods start from cyanogen iodide.

[3] Tetramethylguanidine is mainly used as a strong, non-nucleophilic base for alkylations, often as a substitute for the more expensive DBU and DBN.

[3] Since it is highly water-soluble, it is easily removed from mixtures in organic solvents.