2C-T-15 or 2,5-dimethoxy-4-(β-cyclopropylthio)phenethylamine is a psychedelic phenethylamine of the 2C family. It was presumably first synthesized by Alexander Shulgin and reported in his book PiHKAL (Phenethylamines i Have Known And Loved).

2C-T-15 is the 2 carbon homologue of Aleph-15, which has not been synthesized. The full chemical name is 2-[4-(2-cyclopropylthio)-2,5-dimethoxyphenyl]ethanamine. The drug has structural properties similar to 2C-T-2 and other drugs in the 2C-T series.

The dosage range of 2C-T-15 is typically 30 mg or more. Its duration is unspecified by Shulgin, and its entry in PiHKAL says it lasts for "several hours." The effects are not prominent, and 2C-T-15 is not very potent.

The mechanism that produces 2C-T-15's hallucinogenic and entheogenic effects has not been specifically established, however it is most likely to result from action as a 5-HT_2A serotonin receptor agonist in the brain, a mechanism of action shared by all of the hallucinogenic tryptamines and phenethylamines for which the mechanism of action is known.