Introduction: Gamma-aminobutyric acid (GABA), the main inhibitory neurotransmitter in the central nervous system, plays a pivotal role in synchronization of local neural networks and coupling of brain regions functions. GABA is synthesized in the brain by a metabolic pathway known as ‘GABA shunt’ as it does not cross the blood-brain barrier. There are three types of GABA receptors named GABA_A, GABA_B and GABA_C, which in turn are divided into two classes of ionotropic and metabotropic receptors. Ionotropic receptors of GABA including GABA_A and GABA_C receptors are ligand-gated ion channels, permit influx of chloride ion into neurons after activation, hyperpolarize membrane potential, and subsequently inhibit firing of new action potentials. GABA_A receptors are heteropentameres of eight subunits including α, β, γ, δ, ε, θ, π and ρ, which some subunits have more than one isoform. Expression of α1, β2, γ2 subunits of the GABA_A receptors in the brain is dominant. GABA_C receptors only consist of ρ subunits. GABA_B metabotropic receptors belong to G-protein coupled receptors, which via second messengers abolish calcium influx, increase potassium efflux, and decrease cAMP level in neurons. GABA_B receptors are heterodimers of GABA_B1 and GABA_B2 subunits. Changes in expression of GABA receptors in different brain regions may cause some neuropsychological disorders, including schizophrenia, epilepsy, anxiety, sleep disorder and autism spectrum disorders. Conclusion: With knowledge of diversities in subunit structure of GABA receptors in different brain areas, it is possible to treat neural disorders more effectively.