Amacrine cells produce a complex array of inhibition to bipolar cells, ganglion cells, and other amacrine cells. Gamma-aminobutyric acid (GABA) and glycine are the primary inhibitory neurotransmitters, each contained in about 35% of all amacrine cells, with little coexpression. Both provide feedback inhibition to bipolar cells, although GABAergic feedback is more prominent. It is most evident in ON bipolar cells, where the GABA_C receptor is particularly important. This feedback improves spatial and temporal contrast and increases the dynamic range at the synapse. There is lateral inhibition between amacrine cells, notably long-range glycinergic inhibition. Both GABAergic and glycinergic amacrine cells feed forward to inhibit ganglion cells. They produce sustained and transient surround inhibition that shortens the response time and improves the resolution of ganglion cells. Glycinergic synapses are often responsible for transient inhibition. There are also inhibitory GABAergic bipolar cells and both glycinergic and GABAergic interplexiform cells. This chapter reviews the history of inhibitory amino acid neurotransmitters in retina, the properties of the receptors, the synaptic mechanisms, and the retinal circuits.