Purpose This study was conducted to identify the effect of insights on medication adherence in patients with schizophrenia. Design and methods This is a cross-sectional study conducted between June 2017 and June 2018 in the Elazig Mental Health and Diseases Hospital. The sample of the study was determined as 300 patients with schizophrenia with the power analysis. Descriptive Characteristics Form, Birchwood Insight Scale, and Morisky Medication Adherence Scale were used to collect the data. In the analysis of data, percentage, arithmetic mean, independent samples t test, the Kruskal Wallis test, analysis of variance, regression analysis, and post hoc-Tukey tests were used. Findings Approximately 69% of the patients had a moderate level of medication adherence and moderate insight. There was a statistically positive strong correlation between the insights and medication adherence of the patients (P < .05). Practise implications The patients with schizophrenia had low insight and moderate medication adherence and as their insight increased their medication adherence increased.