Ψ-Phenethylamines (Ψ-PEA), or psi-phenethylamines (psi-PEA), also known as pseudo-phenethylamines or as 4-substituted 2,6-dimethoxyphenethylamines, are a family of psychedelic and related compounds of the phenethylamine family. They are positional isomers of the 4-substituted 2,5-dimethoxyphenethylamines (e.g., 2Cs and DOx) and 4-substituted 3,5-dimethoxyphenethylamines (e.g., scalines and 3Cs).

Like the preceding groups or substitution patterns of phenethylamine psychedelics, many Ψ-PEA derivatives are potent serotonergic psychedelics and are known to act as serotonin 5-HT_2A receptor agonists. Examples of known psychedelic Ψ-PEAs include TMA-6 (Ψ-TMA-2), Ψ-DOM, Ψ-2C-T-4, Ψ-2C-DFMO, Ψ-DODFMO, and 2,4,6-TMPEA-NBOMe (26O-NBOMe; ψ-2C-O-NBOMe). Conversely, Ψ-2C-O (TMPEA-6) was inactive. Unlike many other psychedelic phenethylamines, Ψ-PEAs such as TMA-6, Ψ-Aleph, and Ψ-Aleph-2 are known to act as potent monoamine oxidase inhibitors (MAOIs).

The Ψ-PEAs are relatively unexplored compared to the other major psychedelic phenethylamine groups. Many Ψ-PEAs have been synthesized or described, but few are known to have been tested in humans.

The receptor interactions of Ψ-PEAs and their amphetamine counterparts have been studied and described. They are partial agonists of the serotonin 5-HT_2A receptor and also interact with other serotonin receptors and targets.

Other ψ-PEAs have also been described. Another notable ψ-PEA is ψ-2C-D-FLY.

The Ψ-PEA drugs are controlled substances in Canada under phenethylamine blanket-ban language.