Purpose To examine the effect of motivational interview (MI) on treatment adherence and insight of the patients diagnosed with schizophrenia at a hospital in Turkey. Design and Methods Individuals with schizophrenia, who match with the sample characteristics, were assigned to intervention (20) and control groups (20) according to the randomization schedule. Personal Information Form, Self-Reported Measure of Medication Adherence, and Schedule for Assessing the Three Components of Insight were used. Findings Group-wise examinations showed that mean scores of "three component scales of insight" yielded statistically significant difference for the intervention group. Analysis of the Treatment Adherence Scale Mean Scores showed a significant difference for interval mean scores of the intervention group. Practice Implications Both the pyschiatric patients and the health institutions can benefit from increased levels of treatment adherence and insight by the adoption of the MI methods starting with a patient's first registration to a psychiatric outpatient clinic. Implications for Nursing Practice MI can be included during any of the patient visits to establish treatment collaboration with psychiatric patients at psychiatric facilities, outpatient clinics, and community mental health centers.