Purpose This study evaluated the impact of nurse‐led medication adherence therapy (MAT) on medication adherence behavior and symptom severity of inpatients with bipolar disorder. Method Two arms, single‐blind, randomized controlled trial on individuals with bipolar disorder was conducted at inpatient department of mental healthcare setting, India. Eighty‐five participants were randomly allocated to MAT group and Treatment as usual group. Standard measures were used to assess medication adherence and symptom severity of both groups at baseline and follow‐up time points. Conclusion MAT improved medication adherence behavior resulting in marked decrease in symptom severity of participants with bipolar disorders. Implications for Nursing Practice Psychiatric nurses can effectively implement MAT for bipolar inpatients, which improves better clinical outcomes, prevent relapse, and readmissions.