A monoamine receptor is a receptor for the monoamine neurotransmitters and/or trace amines, endogenous small-molecule signaling molecules with a monoamine structure. The monoamine receptors are almost all G protein-coupled receptors, with the serotonin 5-HT3 receptor being a notable exception as a ligand-gated ion channel. Monoamine receptors are the biological targets of many drugs; such drugs may be referred to as "monoaminergic".
Monoamine receptors include the following classes: