Background: Heart failure is often associated with sleep disturbances that negatively impact physical health, cognitive function, daily activities, mental health, and disease prognosis. Complementary therapies need to be implemented to address sleep disturbances in patients with heart failure. Objective: This systematic review aims to identify complementary therapies for improving sleep quality in patients with heart failure. Methods: This study uses a systematic review design based on the formulation of PICO (Population, Intervention, Comparison, and Outcome). The search strategy followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and was conducted in November 2022 using online databases, including ClinicalKey Nursing, Taylor & Francis, ProQuest, SAGE Journals, ScienceDirect, Scopus, and SpringerLink. Articles were selected based on the following criteria: publication in international journals within the previous 5 years; publication in English; use of an experimental research design, including randomized controlled trials (RCTs) or quasi-experimental studies; and inclusion of adult patients (aged >18 years). Results: Seven research articles met the inclusion criteria. The studies showed that complementary therapies can improve sleep quality in patients with heart failure. Complementary therapies recommended for use in outpatient settings include listening to classical music, brief behavioral treatment for insomnia, cognitive behavioral therapy for insomnia, aromatherapy, and sleep intervention programs. Conclusion: Complementary therapies that can be implemented in inpatient settings include leg thermal therapy and aromatherapy.