This article reviews what causes clinicians to overlook or underdiagnose akathisia. The causes are considered to be related to both the patient's symptoms and the clinician's attitude toward akathisia. The patient factors include mild severity of akathisia, lack of apparent motor restlessness, no voluntary expression of inner restlessness, no clear communication of inner restlessness, restlessness in body parts other than the legs, atypical expressions of inner restlessness, other prominent psychic symptoms, and absence of other extrapyramidal signs. The clinician factors include emphasis on objective restlessness, failure to consider akathisia during antipsychotic therapy, failure to fully implement antiakathisia treatments in ambiguous cases, and strict adherence to research diagnostic criteria. Akathisia is likely to be overlooked or underdiagnosed when both patient and clinician factors are present. Currently, there may be two major problems with underdiagnosis: (1) symptoms that fulfill the diagnostic criteria for akathisia are overlooked, and (2) conditions that do not fulfill the diagnostic criteria but can still benefit from antiakathisia measures are underdiagnosed.