L-3,4-Dihydroxyphenylalanine (DOPA), a precursor of a neurotransmitter dopamine (DA), is a neurotransmitter candidate in the central nervous system. GPR143 was shown to function as a receptor for L-DOPA. Recently, we found that DOPA positively regulates DA D2 receptor (D2R) function through coupling GPR143 and D2R. In this study, we carried out a comprehensive behavioral analysis of Gpr143 gene-deficient (Gpr143^-/y) mice. We found that Gpr143^-/y mice exhibited behavioral abnormalities related to symptoms of psychiatric disorders. In the novel-object-recognition task, wild type (Wt) and Gpr143^-/y mice exhibited similar preferences toward the novel object at the 30-minute retention test, but at the 24-hour retention test, Gpr143^-/y mice spent significantly less time exploring the novel object than Wt mice. The Gpr143^-/y mice showed enhanced sucrose preference in two- bottle preference test, greater aggression in tube dominant test, and impaired prepulse inhibition in prepulse inhibition test. In the forced swim test, Gpr143^-/y mice tended to become immobile more rapidly and exhibited a longer duration of immobility than Wt mice. These findings suggest that GPR143 plays a role in brain functions related to long-term memory, sensory gating system, social behavior and emotion.